Method and Compositions for Treating Viral Infection

ABSTRACT

A method of treating viral infection, such as viral infection caused by a virus of the Filoviridae family, Flaviviridae family (Flavivirus genus), Deltaretrovirus genus, or Togaviriade family is provided. A composition having at least one cardiac glycoside is used to treat viral infection. The composition can futher include at least one triterpene. Alternatively, the composition comprises at least one, at least two, or at least three triterpenes.

CROSS-REFERENCE TO EARLIER FILED APPLICATIONS

The present application claims the benefit of and is a continuation ofSer. No. 16/815,260 filed Mar. 11, 2020, which is a continuation of Ser.No. 16/803,488 filed Feb. 27, 2020, which is a continuation of Ser. No.16/779,840 filed Feb. 3, 2020, which is a continuation of Ser. No.16/747,637 filed Jan. 21, 2020, which is a continuation of applicationSer. No. 16/424,902 filed May 29, 2019, which is a continuation-in-partof application Ser. No. 16/276,063 filed Feb. 14, 2019, which is acontinuation of application No. PCT/US18/42226 filed Jul. 16, 2018,which is a continuation-in-part of application No. PCT/US17/51553 filedSep. 14, 2017, and said application No. PCT/US18/42226 also claims thebenefit of provisional application No. 62/698,365 filed Jul. 16, 2018,and said application Ser. No. 16/276,063 is also a continuation-in-partof said application No. PCT/US17/51553, which claims the benefit ofprovisional application No. 62/394,504 filed Sep. 14, 2016, and saidapplication Ser. No. 16/424,902 claims the benefit of provisionalapplication No. 62/853,838 filed May 29, 2019, the entire disclosures ofwhich are hereby incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with government support under grant No.1R15CA202265-01A1 awarded by the National Cancer Institute/NationalInstitutes of Health (NIH) to Dr. Robert Harrod. The U.S. Government hascertain rights in the invention.

FIELD OF THE INVENTION

The present invention concerns an antiviral composition and its use fortreating Flaviviridae infection, Togaviridae infection, or Filoviridaeinfection in mammals. Some embodiments concern treatment of hemorrhagicviral infection.

BACKGROUND OF THE INVENTION

Nerium oleander, a member of the Nerium species, is an ornamental plantwidely distributed in subtropical Asia, the southwestern United States,and the Mediterranean. Its medical and toxicological properties havelong been recognized. It has been proposed for use, for example, in thetreatment of hemorrhoids, ulcers, leprosy, snake bites, cancers, tumors,neurological disorders, cell-proliferative diseases.

Extraction of components from plants of Nerium species has traditionallybeen carried out using boiling water, cold water, or organic solvent.

ANVIRZEL™ (U.S. Pat. No. 5,135,745 to Ozel), which is commerciallyavailable, contains the concentrated form or powdered form of thehot-water extract of Nerium oleander. Muller et al. (Pharmazie. (1991)September 46(9), 657-663) disclose the results regarding the analysis ofa water extract of Nerium oleander. They report that the polysaccharidepresent is primarily galacturonic acid. Other saccharides includerhamnose, arabinose and galactose. Polysaccharide content and individualsugar composition of polysaccharides within the hot water extract ofNerium oleander have also been reported by Newman et al. (J HerbalPharmacotherapy, (2001) vol 1, pp. 1-16). U.S. Pat. No. 5,869,060 toSelvaraj et al. pertains to extracts of Nerium species and methods ofproduction. To prepare the extract, plant material is placed in waterand boiled. The crude extract is then separated from the plant matterand sterilized by filtration. The resultant extract can then belyophilized to produce a powder. U.S. Pat. No. 6,565,897 (U.S. PregrantPublication No. 20020114852 and PCT International Publication No. WO2000/016793 to Selvaraj et al.) discloses a hot-water extraction processfor the preparation of a substantially sterile extract.

Erdemoglu et al. (J. Ethnopharmacol. (2003) November 89(1), 123-129)discloses results for the comparison of aqueous and ethanolic extractsof plants, including Nerium oleander, based upon their anti-nociceptiveand anti-inflammatory activities.

Organic solvent extracts of Nerium oleander are also disclosed by Adomeet al. (Afr. Health Sci. (2003) August 3(2), 77-86; ethanolic extract),el-Shazly et al. (J. Egypt Soc. Parasitol. (1996), August 26(2),461-473; ethanolic extract), Begum et al. (Phytochemistry (1999)February 50(3), 435-438; methanolic extract), Zia et al. (J.Ethnolpharmacol. (1995) November 49(1), 33-39; methanolic extract), andVlasenko et al. (Farmatsiia. (1972) September-October 21(5), 46-47;alcoholic extract).

A supercritical fluid extract of Nerium species is known (U.S. Pat. Nos.8,394,434, 8,187,644, 7,402,325) and has demonstrated efficacy intreating neurological disorders (U.S. Pat. Nos. 8,481,086, 9,220,778,9,358,293, US 20160243143A1) and cell-proliferative disorders (U.S. Pat.No. 8,367,363).

Triterpenes are known to possess a wide variety of therapeuticactivities. Some of the known triterpenes include oleanolic acid,ursolic acid, betulinic acid, bardoxolone, maslinic acid, and others.The therapeutic activity of the triterpenes has primarily been evaluatedindividually rather than as combinations of triterpenes.

Oleanolic acid is in a class of triterpenoids typified by compounds suchas bardoxolone which have been shown to be potent activators of theinnate cellular phase 2 detoxifying pathway, in which activation of thetranscription factor Nrf2 leads to transcriptional increases in programsof downstream antioxidant genes containing the antioxidanttranscriptional response element (ARE). Bardoxolone itself has beenextensively investigated in clinical trials in inflammatory conditions;however, a Phase 3 clinical trial in chronic kidney disease wasterminated due to adverse events that may have been related to knowncellular toxicities of certain triterpenoids including bardoxolone atelevated concentrations.

Compositions containing triterpenes in combination with othertherapeutic components are found as plant extracts. Fumiko et al. (Biol.Pharm. Bull (2002), 25(11), 1485-1487) discloses the evaluation of amethanolic extract of Rosmarimus officinalis L. for treatingtrypanosomiasis. Addington et al. (U.S. Pat. Nos. 8,481,086, 9,220,778,9,358,293, US 20160243143 A1) disclose a supercritical fluid extract(SCF; PBI-05204) of Nerium oleander containing oleandrin and triterpenesfor the treatment of neurological conditions. Addington et al. (U.S.Pat. No. 9,011,937, US 20150283191 A1) disclose a triterpene-containingfraction (PBI-04711) of the SCF extract of Nerium oleander containingoleandrin and triterpenes for the treatment of neurological conditions.Jager et al. (Molecules (2009), 14, 2016-2031) disclose various plantextracts containing mixtures of oleanolic acid, ursolic acid, betulinicacid and other components. Mishra et al. (PLoS One 2016 25;11(7):e0159430. Epub 2016 Jul. 25) disclose an extract of Betula utilisbark containing a mixture of oleanolic acid, ursolic acid, betulinicacid and other components. Wang et al. (Molecules (2016), 21, 139)disclose an extract ofAlstonia scholaris containing a mixture ofoleanolic acid, ursolic acid, betulinic acid and other components. L. eSilva et al. (Molecules (2012), 17, 12197) disclose an extract of Eriopeblanchetti containing a mixture of oleanolic acid, ursolic acid,betulinic acid and other components. Rui et al. (Int. J. Mol. Sci.(2012), 13, 7648-7662) disclose an extract of Eucaplyptus globuluscontaining a mixture of oleanolic acid, ursolic acid, betulinic acid andother components. Ayatollahi et al. (Iran. J. Pharm. Res. (2011), 10(2),287-294) disclose an extract of Euphorbia microsciadia containing amixture of oleanolic acid, ursolic acid, betulinic acid and othercomponents. Wu et al. (Molecules (2011), 16, 1-15) disclose an extractof Ligustrum species containing a mixture of oleanolic acid, ursolicacid, betulinic acid and other components. Lee et al. (Biol. Pharm. Bull(2010), 33(2), 330) disclose an extract of Forsythia viridissimacontaining a mixture of oleanolic acid, ursolic acid, betulinic acid andother components.

Oleanolic acid (O or OA), ursolic acid (U or UA) and betulinic acid (Bor BA) are the three major triterpene components found in PBI-05204(PBI-23; a supercritical fluid extract of Nerium oleander) and PBI-04711(a triterpene-containing fraction 0-4 of PBI-05204). We (two of theinstant inventors) previously reported (Van Kanegan et al., in NatureScientific Reports (May 2016), 6:25626. doi: 10.1038/srep25626) on thecontribution of the triterpenes toward efficacy by comparing theirneuroprotective activity in a brain slice oxygen glucose deprivation(OGD) model assay at similar concentrations. We found that PBI-05204(PBI) and PBI-04711 (Fraction 0-4) provide neuroprotective activity.

Extracts of Nerium species are known to contain many different classesof compounds: cardiac glycosides, glycones, steroids, triterpenes,polysaccharides and others. Specific compounds include oleandrin;neritaloside; odoroside; oleanolic acid; ursolic acid; betulinic acid;oleandrigenin; oleaside A; betulin (urs-12-ene-3β, 28-diol);28-norurs-12-en-3β-ol; urs-12-en-3β-ol; 3β, 3β-hydroxy-12-oleanen-28-oicacid; 3β, 20α-dihydroxyurs-21-en-38-oic acid; 3β,27-dihydroxy-12-ursen-38-oic acid; 3β, 13β-dihydroxyurs-11-en-28-oicacid; 3β, 12α-dihydroxyoleanan-28,13β-olide; 3β,27-dihydroxy-12-oleanan-28-oic acid; and other components.

Viral hemorrhagic fever (VHF) can be caused by five distinct virusfamilies: Arenaviridae, Bunyaviridae, Filoviridae, Flaviviridae, andParamyxoviridae. The Filoviruses, e.g. Ebolavirus (EBOV) andMarburgvirus (MARV), are among the most pathogenic viruses known to manand the causative agents of viral hemorrhagic fever outbreaks withfatality rates of up to 90%. Each virion contains one molecule ofsingle-stranded, negative-sense RNA. Beyond supportive care orsymptomatic treatment, there are no commercial therapeutically effectivedrugs and no prophylactic drugs available to treat EBOV (Eboval virus)and MARV (Marburg virus) infections, i.e. filovirus infections. Fivespecies of Ebolavirus have been identified: Tai Forest (formerly IvoryCoast), Sudan, Zaire, Reston and Bundibugyo.

The Flaviviruses are positive, single-stranded, enveloped RNA viruses.They are found in arthropods, primarily ticks and mosquitoes, and causewidespread morbidity and mortality throughout the world. Some of themosquito-transmitted viruses include Yellow Fever, Dengue Fever,Japanese Enchephalitis, West Nile Viruses, and Zikavirus. Some of thetick-transmitted viral infections include Tick-borne Encephalitis,Kyasanur Forest Disease, Alkhurma Disease, Omsk Hemorrhagic Fever.Although not a hemorrhagic infection, Powassan virus is a Flavivirus.

Oleandrin, and an extract of Nerium oleander have been shown to preventthe incorporation of the gp120 envelope glycoprotein of HIV-1 intomature virus particles and inhibit viral infectivity in vitro (Singh etal., “Nerium oleander derived cardiac glycoside oleandrin is a novelinhibitor of HIV infectivity” in Fitoterapia (2013) 84, 32-39).

Oleandrin has demonstrated anti-HIV activity but has not been evaluatedagainst many viruses. The triterpenes oleanolic acid, betulinic acid andursolic acid have been reported to exhibit differing levels of antiviralactivity but have not been evaluated against many viruses. Betulinicacid has demonstrated some anti-viral activity against HSV-1 strain 1C,influenza A H7N1, ECHO 6, and HIV-1. Oleanolic acid has demonstratedsome anti-viral activity against HIV-1, HEP C, and HCV H strain NS5B.Ursolic acid has demonstrated some anti-viral activity against HIV-1,HEP C, HCV H strain NS5B, HSV-1, HSV-2, ADV-3, ADV-8, ADV-11, HEP B,ENTV CVB1 and ENTV EV71. The antiviral activity of oleandrin, oleanolicacid, ursolic acid and betulinic acid is unpredictable as far asefficacy against specific viruses. Viruses exist against whicholeandrin, oleanolic acid, ursolic acid and/or betulinic acid havelittle to no antiviral activity, meaning one cannot predic a prioriwhether oleandrin, oleanolic acid, ursolic acid and/or betulinic acidwill exhibit antiviral activity against particular genuses of viruses.

Barrows et al. (“A screen of FDA-approved drugs for inhibitors ofZikavirus infection” in Cell Host Microbe (2016), 20, 259-270) reportthat digoxin demonstrates antiviral activity against Zikavirus but thedoses are too high and likely toxic. Cheung et al. (“Antiviral activityof lanatoside C against dengue virus infection” in Antiviral Res. (2014)111, 93-99) report that lanatoside C demonstrates antiviral activityagainst Dengue virus.

Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus belonging tothe family Retroviridae and the genus deltaretrovirus. It has apositive-sense RNA genome that is reverse transcribed into DNA and thenintegrated into the cellular DNA. Once integrated, HTLV-1 continues toexist only as a provirus which can spread from cell to cell through aviral synapse. Few, if any, free virions are produced, and there isusually no detectable virus in the blood plasma though the virus ispresent in genital secretions. HTLV-1 predominately infectsCD4+T-lymphocytes and causes adult T-cell leukemia/lymphoma (ATLL)—arare, yet aggressive hematological malignancy with high rates oftherapy-resistance and generally poor clinical outcomes, in addition toseveral autoimmune/inflammatory conditions, including infectiousdermatitis, rheumatoid arthritis, uveitis, keratoconjunctivitis, siccasyndrome, Sjögren's syndrome, and HAM/TSP, among others. HAM/TSP isclinically characterized by chronic progressive spastic paraparesis,urinary incontinence, and mild sensory disturbance. While ATLL isetiologically linked to viral latency, oncogenic transformation, and theclonal expansion of HTLV-1-infected cells, the inflammatory diseases,such as HTLV-1-associated myelopathy/tropical spastic paraparesis(HAM/TSP), are caused by autoimmune and/or immunopathological responsesto proviral replication and the expression of viral antigens. HAM/TSP isa progressive neuroinflammatory disease that results in thedeterioration and demyelination of the lower spinal cord.HTLV-1-infected circulating T-cells invade the central nervous system(CNS) and cause an immunopathogenic response against virus and possiblycomponents of the CNS. Neural damage and subsequent degeneration cancause severe disability in patients with HAM/TSP. The persistence ofproviral replication and the proliferation of HTLV-1-infected cells inthe CNS leads to a cytotoxic T-cell response targeted against viralantigens, and which may be responsible for the autoimmune destruction ofnervous tissues.

Even though cardiac glycosides have been demonstrated to exhibit someantiviral activity against a few viruses, the specific compounds exhibitvery different levels of antiviral activity against different viruses,meaning that some exhibit very poor antiviral activity and some exhibitbetter antiviral activity when evaluated against the same virus(es).

A need remains for improved pharmaceutical compositions containingoleandrin, oleanolic acid, ursolic acid, betulinic acid or anycombination thereof that are therapeutically active against specificviral infections.

SUMMARY OF THE INVENTION

The invention provides a pharmaceutical composition and method fortreating viral infection in a mammalian subject. The invention alsoprovides a pharmaceutical composition and method for treating viralinfection, e.g. Viral hemorrhagic fever (VHF) infection, in a mammaliansubject. The invention also provides a method of treating viralinfection in mammals by administration of the pharmaceuticalcomposition. The inventors have succeeded in preparing antiviralcompositions that exhibit sufficient antiviral activity to justify theiruse in treating viral infection in humans and animals. The inventorshave developed corresponding treatment methods employing particulardosing regimens.

In some embodiments, the viral infection is caused by any of thefollowing virus families: Arenaviridae, Bunyaviridae, Filoviridae,Flaviviridae, Paramyxoviridae, Retroviridae (in particular,Deltaretrovirus genus), or Togaviridae.

Some embodiments of the invention are directed to compositions for andmethods of treating Filovirus infection, Flavivirus infection,Henipavirus infection, alphavirus infection, or Togavirus infection.Viral infections that can be treated include, at least, Ebolavirus,Marburgvirus, Alphavirus, Flavivirus, Yellow Fever, Dengue Fever,Japanese Enchephalitis, West Nile Viruses, Zikavirus, Venezuelan EquineEncephalomyelitis (encephalitis) (VEE) virus, Chikungunya virus, WesternEquine Encephalomyelitis (encephalitis) (WEE) virus, Eastern EquineEncephalomyelitis (encephalitis) (EEE) virus, Tick-borne Encephalitis,Kyasanur Forest Disease, Alkhurma Disease, Omsk Hemorrhagic Fever,Hendra virus, Nipah virus, Deltaretrovirus genus, HTLV-1 virus, andspecies thereof.

Some embodiments of the invention are directed to compositions for andmethods of treating viral infections from viruses of the Filoviridaefamily, Flavivirudae family (Flavivirus genus), Paramyxoviridae family,Retroviridae family (Deltaretrovirus genus), or Togaviridae family.

Some embodiments of the invention are directed to compositions for andmethods of treating viral infections from viruses of the Henipavirusgenus, Ebolavirus genus, Flavivirus genus, Marburgvirus genus,Deltaretrovirus genus, or Alphavirus genus.

The invention also provides embodiments for the treatment ofHTLV-1-associated condition or neuro-inflammatory disease. In someembodiments, the HTLV-1-associated condition or neuro-inflammatorydisease is selected from the group consisting of myelopathy/tropicalspastic paraparesis (HAM/TSP), adult T-cell leukemia/lymphoma (ATLL),autoimmune condition, inflammatory condition, infectious dermatitis,rheumatoid arthritis, uveitis, keratoconjunctivitis, sicca syndrome,Sjögren's syndrome, and Strongyloides stercoralis.

The invention also provides a method of inhibiting the infectivity ofHTLV-1 particles released into the culture supernatants of treated cellsand also reducing the intercellular transmission of HTLV-1 by inhibitingthe Env-dependent formation of virological synapses, the methodcomprising administering to a subject in need thereof an effectiveamount of the antiviral composition.

In some embodiments, the invention provides an antiviral compositioncomprising (consisting essentially of): a) specific cardiacglycoside(s); b) plural triterpenes; or c) a combination of specificcardiac glycoside(s) and plural triterpenes.

One aspect of the invention provides a method of treating viralinfection in a subject by chronic administration to the subject of anantiviral composition. The subject is treated by chronicallyadministering to the subject a therapeutically effective amount(therapeutically relevant dose) of the composition, thereby providingrelief of symptoms associated with the viral infection or ameliorationof the viral infection. Administration of the composition to the subjectcan begin immediately after infection or any time within one day to 5days after infection or at the earliest time after definite diagnosis ofinfection with virus.

Accordingly, the invention also provides a method of treating viralinfection in a mammal, the method comprising administering to the mammalone or more therapeutically effective doses of the antiviralcomposition. One or more doses are administered on a daily, weekly ormonthly basis. One or more doses per day can be administered.

The invention also provides a method of treating viral infection in asubject in need thereof, the method comprising:

-   determining whether or not the subject has a viral infection;-   indicating administration of antiviral composition;-   administering an initial dose of antiviral composition to the    subject according to a prescribed initial dosing regimen for a    period of time;-   periodically determining the adequacy of subject's clinical response    and/or therapeutic response to treatment with antiviral composition;    and-   if the subject's clinical response and/or therapeutic response is    adequate, then continuing treatment with antiviral composition as    needed until the desired clinical endpoint is achieved; or-   if the subject's clinical response and/or therapeutic response are    inadequate at the initial dose and initial dosing regimen, then    escalating or deescalating the dose until the desired clinical    response and/or therapeutic response in the subject is achieved.

Treatment of the subject with antiviral composition is continued asneeded. The dose or dosing regimen can be adjusted as needed until thepatient reaches the desired clinical endpoint(s) such as a reduction oralleviation of specific symptoms associated with the viral infection.Determination of the adequacy of clinical response and/or therapeuticresponse can be conducted by a clinician familiar with viral infections.

The individual steps of the methods of the invention can be conducted atseparate facilities or within the same facility.

The antiviral composition can be administered chronically, i.e. on arecurring basis, such as daily, every other day, every second day, everythird day, every fourth day, every fifth day, every sixth day, weekly,every other week, every second week, every third week, monthly,bimonthly, semi-monthly, every other month every second month,quarterly, every other quarter, trimesterly, seasonally, semi-annuallyand/or annually. The treatment period one or more weeks, one or moremonths, one or more quarters and/or one or more years. An effective doseof cardiac glycoside is administered one or more times in a day;

In some embodiments, the subject is administered 140 microg to 315microg per day of cardiac glycoside. In some embodiments, a dosecomprises 20 microg to 750 microg, 12 microg to 300 microg, or 12 microgto 120 microg of cardiac glycoside. The daily dose of cardiac glycosidecan range from 20 microg to 750 microg, 0.01 microg to 100 mg, or 0.01microg to 100 microg of cardiac glycoside/day. The recommended dailydose of oleandrin, present in the SCF extract, is generally about 0.25to about 50 microg twice daily or about 0.9 to 5 microg twice daily orabout every 12 hours. The dose can be about 0.5 to about 100 microg/day,about 1 to about 80 microg/day, about 1.5 to about 60 microg/day, about1.8 to about 60 microg/day, about 1.8 to about 40 microg/day. Themaximum tolerated dose can be about 100 microg/day, about 80 microg/day,about 60 microg/day, about 40 microg/day, about 38.4 microg/day or about30 microg/day of oleander extract containing oleandrin and the minimumeffective dose can be about 0.5 microg/day, about 1 microg/day, about1.5 microg/day, about 1.8 microg/day, about 2 microg/day, or about 5microg/day. Suitable doses comprising cardiac glycoside and triterpenecan be about 0.05-0.5 mg/kg/day, about 0.05-0.35 mg/kg/day, about0.05-0.22 mg/kg/day, about 0.05-0.4 mg/kg/day, about 0.05-0.3 mg/kg/day,about 0.05-0.5 microg/kg/day, about 0.05-0.35 microg/kg/day, about0.05-0.22 microg/kg/day, about 0.05-0.4 microg/kg/day, or about 0.05-0.3microg/kg/day.

The antiviral composition can be administered systemically. Modes ofsystemic administration include parenteral, buccal, enteral,intramuscular, subdermal, sublingual, peroral, or oral. The compositioncan also be administered via injection or intravenously.

If present in the antiviral composition, the cardiac glycoside ispreferably oleandrin but can also include odoroside, neritaloside, oroleandrigenin. In some embodiments, the composition further comprises:a) one or more triterpenes; b) one or more steroids; c) one or moretriterpene derivatives; d) one or more steroid derivatives; or e) acombination thereof. In some embodiments, the composition comprisescardiac glycoside and: a) two or three triterpenes; b) two or threetriterpene derivatives; c) two or three triterpene salts; or d) acombination thereof. In some embodiments, the triterpene is selectedfrom the group consisting of oleanolic acid, ursolic acid, betulinicacid and salts or derivatives thereof.

Some embodiments of the invention include those wherein a pharmaceuticalcomposition comprises at least one pharmaceutical excipient and theantiviral composition. In some embodiments, the antiviral compositioncomprises: a) at least one cardiac glycoside and at least onetriterpene; b) at least one cardiac glycoside and at least twotriterpenes; c) at least one cardiac glycoside and at least threetriterpenes; d) at least two triterpenes and excludes cardiac glycoside;e) at least three triterpenes and excludes cardiac glycoside; or f) atleast one cardiac glycoside, e.g. oleandrin. As used herein, the genericterms triterpene and cardiac glycoside also encompass salts andderivatives thereof, unless otherwise specified.

The cardiac glycoside can be present in a pharmaceutical composition inpure form or as part of an extract containing one or more cardiacglycosides. The triterpene(s) can be present in a pharmaceuticalcomposition in pure form or as part of an extract containingtriterpene(s). In some embodiments, the cardiac glycoside is present asthe primary therapeutic component, meaning the component primarilyresponsible for antiviral activity, in the pharmaceutical composition.In some embodiments, the triterpene(s) is/are present as the primarytherapeutic component(s), meaning the component(s) primarily responsiblefor antiviral activity, in the pharmaceutical composition.

In some embodiments, an extract comprising the antiviral composition isobtained by extraction of plant material. The extract can comprise ahot-water extract, cold-water extract, supercritical fluid (SCF)extract, organic solvent extract, or combination thereof of the plantmaterial. In some embodiments, the plant material is Nerium species orThevetia species plant mass. Particular species include Nerium oleanderor Thevetia nerifolia. In some embodiments, the extract comprises atleast one other pharmacologically active agent, obtained along with thecardiac glycoside during extraction, that contributes to the therapeuticefficacy of the cardiac glycoside when the extract is administered to asubject. In some embodiments, the composition further comprises one ormore other non-cardiac glycoside therapeutically effective agents, i.e.one or more agents that are not cardiac glycosides. In some embodiments,the composition further comprises one or more antiviral compound(s). Insome embodiments, the antiviral composition excludes a pharmacologicallyactive polysaccharide.

In some embodiments, the extract comprises one or more cardiacglycosides and one or more cardiac glycoside precursors (such ascardenolides, cardadienolides and cardatrienolides, all of which are theaglycone constituents of cardiac glycosides, for example, digitoxin,acetyl digitoxins, digitoxigenin, digoxin, acetyl digoxins, digoxigenin,medigoxin, strophanthins, cymarine, ouabain, or strophanthidin). Theextract may further comprise one or more glycone constituents of cardiacglycosides (such as glucoside, fructoside, and/or glucuronide) ascardiac glycoside presursors. Accordingly, the antiviral composition maycomprise one or more cardiac glycosides and two more cardiac glycosideprecursors selected from the group consisting of one or more aglyconeconstituents, and one or more glycone constituents.

In some embodiments, a composition containing oleandrin (OL), oleanolicacid (OA), ursolic acid (UA) and betulinic acid (BA) is more efficaciousthan pure oleandrin, when equivalent doses based upon oleandrin contentare compared.

In some embodiments, the molar ratio of total triterpene content(OA+UA+BA) to oleandrin ranges from about 15:1 to about 5:1, or about12:1 to about 8:1, or about 100:1 to about 15:1, or about 100:1 to about50:1, or about 100:1 to about 75:1, or about 100:1 to about 80:1, orabout 100:1 to about 90:1, or about 10:1.

In some embodiments, the molar ratios of the individual triterpenes tooleandrin range as follows: about 2-8 (OA):about 2-8 (UA):about 0.1-1(BA):about 0.5-1.5 (OL); or about 3-6 (OA):about 3-6 (UA):about 0.3-8(BA):about 0.7-1.2 (OL); or about 4-5 (OA):about 4-5 (UA):about 0.4-0.7(BA):about 0.9-1.1 (OL); or about 4.6 (OA):about 4.4 (UA):about 0.6(BA):about 1 (OL).

In some embodiments, the other therapeutic agent is not a polysaccharideobtained during preparation of the extract, meaning it is not an acidichomopolygalacturonan or arabinogalaturonan. In some embodiments, theextract excludes another therapeutic agent and/or excludes an acidichomopolygalacturonan or arabinogalaturonan obtained during preparationof the extract.

The invention also provides use of a cardiac glycoside in themanufacture of a medicament for the treatment of viral infection in asubject. In some embodiments, the manufacture of such a medicamentcomprises: providing one or more antiviral compounds of the invention;including a dose of antiviral compound(s) in a pharmaceutical dosageform; and packaging the pharmaceutical dosage form. In some embodiments,the manufacture can be conducted as described in PCT InternationalApplication No. PCT/US06/29061. The manufacture can also include one ormore additional steps such as: delivering the packaged dosage form to avendor (retailer, wholesaler and/or distributor); selling or otherwiseproviding the packaged dosage form to a subject having a viralinfection; including with the medicament a label and a package insert,which provides instructions on use, dosing regimen, administration,content and toxicology profile of the dosage form. In some embodiments,the treatment of viral infection comprises: determining that a subjecthas a viral infection; indicating administration of pharmaceuticaldosage form to the subject according to a dosing regimen; administeringto the subject one or more pharmaceutical dosage forms, wherein the oneor more pharmaceutical dosage forms is administered according to thedosing regimen.

The pharmaceutical composition can further comprise a combination of atleast one material selected from the group consisting of a water soluble(miscible) co-solvent, a water insoluble (immiscible) co-solvent, asurfactant, an antioxidant, a chelating agent, and an absorptionenhancer.

The solubilizer is at least a single surfactant, but it can also be acombination of materials such as a combination of: a) surfactant andwater miscible solvent; b) surfactant and water immiscible solvent; c)surfactant, antioxidant; d) surfactant, antioxidant, and water misciblesolvent; e) surfactant, antioxidant, and water immiscible solvent; f)surfactant, water miscible solvent, and water immiscible solvent; or g)surfactant, antioxidant, water miscible solvent, and water immisciblesolvent.

The pharmaceutical composition optionally further comprises: a) at leastone liquid carrier; b) at least one emulsifying agent; c) at least onesolubilizing agent; d) at least one dispersing agent; e) at least oneother excipient; or f) a combination thereof.

In some embodiments, the water miscible solvent is low molecular weight(less than 6000) PEG, glycol, or alcohol. In some embodiments, thesurfactant is a pegylated surfactant, meaning a surfactant comprising apoly(ethylene glycol) functional group.

The invention includes all combinations of the aspects, embodiments andsub-embodiments of the invention disclosed herein.

BRIEF DESCRIPTION OF THE FIGURES

The following figures form part of the present description and describeexemplary embodiments of the claimed invention. The skilled artisanwill, in light of these figures and the description herein, be able topractice the invention without undue experimentation.

FIGS. 1-2 depict charts summarizing the in vitro dose response antiviralactivity of various compositions against Ebolavirus.

FIGS. 3-4 depict charts summarizing the in vitro dose response antiviralactivity of various compositions against Marburgvirus.

FIG. 5 depicts a chart summarizing the in vitro dose response antiviralactivity of oleandrin against Zikavirus (SIKV strain PRVABC59) in VeroE6 cells.

FIG. 6 depicts a chart summarizing the in vitro dose response antiviralactivity of digoxin against Zikavirus (SIKV strain PRVABC59) in Vero E6cells.

FIG. 7 depicts a chart summarizing the in vitro dose response antiviralactivity of various compositions (oleandrin, digoxin and PBI-05204)against Ebolavirus in Vero E6 cells.

FIG. 8 depicts a chart summarizing the in vitro dose response antiviralactivity of various compositions (oleandrin, digoxin and PBI-05204)against Marburgvirus in Vero E6 cells.

FIG. 9 depicts a chart summarizing the in vitro cellular viability ofVero E6 cells in the presence of various compositions (oleandrin,digoxin and PBI-05204).

FIGS. 10A and 10B depict charts summarizing the ability of compositions(oleandrin and PBI-05204) to inhibit Ebolavirus in Vero E6 cells shortlyafter exposure to virus: FIG. 10A—2 hr post-infection; FIG. 10B—24 hrpost-infection.

FIGS. 11A and 11B depict charts summarizing the ability of compositions(oleandrin and PBI-05204) to inhibit Marburgvirus in Vero E6 cellsshortly after exposure to virus: FIG. 11A—2 hr post-infection; FIG.11B—24 hr post-infection.

FIGS. 12A and 12B depict charts summarizing the ability of compositions(oleandrin and PBI-05204) to inhibit the product of infectious progenyby virally infected Vero E6 cells having been exposed to oleandrin: FIG.12A—Ebolavirus; FIG. 12B-Marburgvirus.

FIGS. 13A and 13B depict charts summarizing the in vitro dose responseantiviral activity of various compositions (oleandrin, digoxin andPBI-05204) against Venezuelen Equine Encephalomyelits virus (FIG. 13A)and Western Equine Encephalomyelitis virus (FIG. 13B) in Vero E6 cells.

FIG. 14 depicts a chart summarizing the effect that vehicle control,oleandrin, or extract of N. oleander have upon HTLV-1 replication or therelease of newly-synthesized virus particles as determined byquantitation of HTLV-1 p19^(Gag) (see Examples 19 and 20). Untreated(UT) cells are shown for comparison. All the data is representative ofat least three independent experiments. The data represent the mean ofthe experiments±standard deviation (error bars).

FIG. 15 depicts a chart summarizing the relative cytotoxicity of theVehicle control, oleandrin, and N. oleander extract against the HTLV-1+SLB1 lymphoma T-cell-line. All the data is representative of at leastthree independent experiments. The data represent the mean of theexperiments±standard deviation (error bars).

FIGS. 16A-16F depict representative micrographs of the Annexin V-FITC(green) and PI (red)-staining results with DIC phase-contrast in themerged images are shown. The individual Annexin V-FITC and PIfluorescent channel images are also provided. Scale bar, 20 μm.

FIG. 17 depicts a chart summarizing the effect that vehicle control,oleandrin, or extract of N. oleander have upon HTLV-1 replication or therelease of newly-synthesized virus particles from oleandrin-treatedHTLV-1+ lymphoma T-cells.

FIG. 18 depicts a chart summarizing the relative cytotoxicity of vehiclecontrol, oleandrin, or extract of N. oleander upon treated huPBMCs.

FIG. 19 depicts a chart summarizing the relative inhibition of HTLV-1transmision in co-culture assays huPBMCs containing vehicle control,oleandrin, or extract of N. oleander.

FIG. 20 depicts representative micrographs of a GFP-expressing HTLV-1+SLB1 T-cell-line: fluorescence-microscopy (top panels) andimmunoblotting (lower panels).

FIG. 21 depicts representative micrographs of virological synapsesbetween huPBMCs and the mitomycin C-treated HTLV-1+ SLB1/pLenti-GFPlymphoblasts (green cells).

FIG. 22 depicts a chart of the averaged data with standard deviation(error bars) from quantitation of the micrographs of FIG. 21.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a method of treating viral infection in a subjectby chronic administration of an effective dose of antiviral composition(or pharmaceutical composition comprising the antiviral composition andat least one pharmaceutical excipient) to the subject. Thepharmaceutical composition is administered according to a dosing regimenbest suited for the subject, the suitability of the dose and dosingregimen to be determined clinically according to conventional clinicalpractices and clinical treatment endpoints for viral infection.

As used herein, the term “subject” is taken to mean warm blooded animalssuch as mammals, for example, cats, dogs, mice, guinea pigs, horses,bovine cows, sheep, and humans.

As used herein, a subject at risk of viral infection is: a) a subjectliving in a geographical area within which mosquitos, in particularAedes species (Aedes egypti, Aedes albopictus) mosquitos, live; b) asubject living with or near a person or people having viral infection;c) a subject having sexual relations with a person having a viralinfection; d) a subject living in a geographical area within whichticks, in particular Ixodes species (Ixodes marx, Ixodes scapularis, orIxodes cooke species) ticks, live; e) a subject living in a geographicalarea within which fruit bats live; f) subjects living in a tropicalregion; g) subjects living in Africa; h) subjects in contact with bodilyfluids of other subjects having a viral infection; i) a child; or j) asubject with a weakened immune system. In some embodiments, the subjectis a female, a female capable of getting pregnant, or a pregnant female.

A subject treated according to the invention will exhibit a therapeuticresponse. By “therapeutic response” is meant that a subject sufferingfrom the viral infection will enjoy at least one of the followingclinical benefits as a result of treatment with a cardiac glycoside:reduction of the active viral titre in the subject's blood or plasma,eradication of active virus from the subject's blood or plasma,amelioration of the infection, reduction in the occurrence of symptomsassociated with the infection, partial or full remission of theinfection or increased time to progression of the infection, and/orreduction in the infectivity of the virus causing said viral infection.The therapeutic response can be a full or partial therapeutic response.

As used herein, “time to progression” is the period, length or durationof time after viral infection is diagnosed (or treated) until theinfection begins to worsen. It is the period of time during which thelevel of infection is maintained without further progression of theinfection, and the period of time ends when the infection begins toprogress again. Progression of a disease is determined by “staging” asubject suffering from the infection prior to or at initiation oftherapy. For example, the subject's health is determined prior to or atinitiation of therapy. The subject is then treated with antiviralcomposition, and the viral titre is monitored periodically. At somelater point in time, the symptoms of the infection may worsen, thusmarking progression of the infection and the end of the “time toprogression”. The period of time during which the infection did notprogress or during which the level or severity of the infection did notworsen is the “time to progression”.

A dosing regimen includes a therapeutically relevant dose (or effectivedose) of one or more cardiac glycosides, and/or triterpene(s),administered according to a dosing schedule. A therapeutically relevantdose, therefore, is a therapeutic dose at which a therapeutic responseof the viral infection to treatment with antiviral composition isobserved and at which a subject can be administered the antiviralcomposition without an excessive amount of unwanted or deleterious sideeffects. A therapeutically relevant dose is non-lethal to a subject,even though it may cause some side effects in the patient. It is a doseat which the level of clinical benefit to a subject being administeredthe antiviral composition exceeds the level of deleterious side effectsexperienced by the subject due to administration of the antiviralcomposition or component(s) thereof. A therapeutically relevant dosewill vary from subject to subject according to a variety of establishedpharmacologic, pharmacodynamic and pharmacokinetic principles. However,a therapeutically relevant dose (relative, for example, to oleandrin)will typically be about about 25 micrograms, about 100 micrograms, about250 micrograms, about 500 micrograms or about 750 micrograms of cardiacglycoside/day or it can be in the range of about 25-750 micrograms ofcardiac glycoside per dose, or might not exceed about 25 micrograms,about 100 micrograms, about 250 micrograms, about 500 micrograms orabout 750 micrograms of cardiac glycoside/day. Another example of atherapeutically relevant dose (relative, for example, to triterpeneeither individually or together) will typically be in the range of about0.1 micrograms to 100 micrograms, about 0.1 mg to about 500 mg, about100 to about 1000 mg per kg of body weight, about 15 to about 25 mg/kg,about 25 to about 50 mg/kg, about 50 to about 100 mg/kg, about 100 toabout 200 mg/kg, about 200 to about 500 mg/kg, about 10 to about 750mg/kg, about 16 to about 640 mg/kg, about 15 to about 750 mg/kg, about15 to about 700 mg/kg, or about 15 to about 650 mg/kg of body weight. Itis known in the art that the actual amount of antiviral compositionrequired to provide a target therapeutic result in a subject may varyfrom subject to subject according to the basic principles of pharmacy.

A therapeutically relevant dose can be administered according to anydosing regimen typically used in the treatment of viral infection. Atherapeutically relevant dose can be administered once, twice, thrice ormore daily. It can be administered every other day, every third day,every fourth day, every fifth day, semiweekly, weekly, biweekly, everythree weeks, every four weeks, monthly, bimonthly, semimonthly, everythree months, every four months, semiannually, annually, or according toa combination of any of the above to arrive at a suitable dosingschedule. For example, a therapeutically relevant dose can beadministered one or more times daily (up to 10 times daily for thehighest dose) for one or more weeks.

Example 15 provides a detailed description of an in vitro assay used toevaluate the efficacy of compositions containing oleandrin (as soleactive), Anvirzel and PBI-05204 (supercritical fluid (SCF) extract ofNerium oleander) for the treatment of Ebolavirus (FIGS. 1-2) andMarburgvirus (FIGS. 3-4) infection, both of which are Filoviruses.

The experiments were set up by adding the compositions to cells at 40microg/mL, then adding virus and incubating for 1 hr. Upon addition ofthe virus to the cells, the final concentration of the compositions is20 microg/mL. Compositions containing different amounts of oleandrin canbe adjusted according to the concentration of oleandrin they contain,and converted that to molarity. FIGS. 1-4 depict the efficacy based onthe oleandrin content of the extracts. OL on its own is efficacious.PBI-05204, the SCF extract of Nerium oleander comprising OL, OA, UA andBA, is substantially more efficacious than OL on its own. Anvirzel, thehot water extract of Nerium oleander, is more efficacious than OL on itsown. Both extracts clearly exhibit efficacy in the nanomolar range. Thepercentage of oleandrin in the PBI-05204 extract (1.74%) is higher thanin Anvirzel (0.459%, 4.59 microg/mg). At the highest dose of PBI-05204,it completely inhibited EBOV and MARV infection, whereas Anvirzel didnot exhibit complete inhibition, because at a dose higher than 20microg/mL with anvirzel, toxicity is observed. The data demonstratehighest antiviral activity against Ebolavirus and Marburgvirus forPBI-05204. The combination of triterpenes in PBI-05204 increased theantiviral activity of oleandrin.

Example 6 provides a detailed description of an in vitro assay used toevaluate the efficacy of the cardiac glycosides for the treatment ofZikavirus (a flavivirus) infection. Vero E6 cells were infected withZika virus (ZIKV strain PRVABC59) at an MOI of 0.2 in the presence ofoleandrin (FIG. 5) or digoxin (FIG. 6). The cells were incubated withvirus and the cardiac glycoside for 1 hr, after which the inoculum andnon-absorbed cardiac glycoside (if any) was removed. The cells wereimmersed in fresh medium and incubated for 48 hr, after which they werefixed with formalin and stained for ZIKV infection. The data demonstrateantiviral activity against Zikavirus for both cardiac glycosides;however, oleandrin exhibited higher (almost 8-fold greater) antiviralactivity than digoxin.

Example 14 provides a detailed description of an assay used to evaluatethe antiviral activity of test compositions against Zikavirus and Denguevirus. The data indicate that oleandrin demonstrates efficacy againstZikavirus and Dengue virus.

FIG. 7 a chart summarizing the in vitro dose response antiviral activityof various compositions (oleandrin, digoxin and PBI-05204) againstEbolavirus (EBOV) in Vero E6 cells. FIG. 8 depicts a chart summarizingthe in vitro dose response antiviral activity of various compositions(oleandrin, digoxin and PBI-05204) against Marburgvirus (MARV) in VeroE6 cells. FIG. 9 depicts a chart summarizing the in vitro cellularviability of Vero E6 cells in the presence of various compositions(oleandrin, digoxin and PBI-05204). For FIGS. 7-8, the host cells wereexposed to the compositions prior to infection with virus. Vero E6 cellswere infected with EBOV/Kik (FIG. 7, MOI=1) or MARV/Ci67 (FIG. 8, MOI=1)in the presence of oleandrin, digoxin or PBI-05204, anoleandrin-containing plant extract. After 1 hr, inoculum and compoundswere removed and fresh medium added to cells. 48 hr later, cells werefixed and immunostained to detect cells infected with EBOV or MARV.Infected cells were enumerated using an Operetta.

In order to ensure that false positives, in terms of antiviral activity,were not being observed, cellular viability in the presence of thecompositions was tested. For the data in FIG. 9, Vero E6 cells weretreated with compound as above. ATP levels were measured byCellTiter-Glo as a measurement of cell viability. It was determined thatoleandrin, digoxin, and PBI-05204 did not reduce cellular viability,meaning that the antiviral activity detailed in other figures herein isnot due to false positives caused by cellular toxicity of the individualcompounds.

Accordingly, the invention provides a method of treating viral infectionin a mammal or host cell, the method comprising: administering anantiviral composition to the mammal or host cell prior to contraction ofsaid viral infection, whereby upon viral infection of said mammal orhost cell, the antiviral composition reduces the viral titre andameliorates, reduces or eliminates the viral infection.

The antiviral composition and method of the invention are also useful intreating viral infection that has occurred prior to administration ofthe antiviral composition. Vero E6 cells were infected with EBOV (FIGS.10A, 10B) or MARV (FIGS. 11A, 11B). At 2 hr post-infection (FIGS. 10A,11A) or 24 hr post-infection (FIGS. 10B, 11B), oleandrin or PBI-05204was added to cells for 1 hr, then discarded and cells were returned toculture medium.

FIGS. 10A and 10B depict charts summarizing the ability of compositions(oleandrin and PBI-05204) to inhibit Ebolavirus in Vero E6 cells shortlyafter exposure to virus: FIG. 10A—2 hr post-infection; FIG. 10B—24 hrpost-infection. When the antiviral composition is administered withintwo hours (or within up to 12 hours) after viral infection, the viraltitre antiviral composition provides effective treatment and reduces theEBOV viral titre. Even after 24 hours, the viral composition iseffective; however, its efficacy is lower as time after initial viralinfection increases. The same evaluations were conducted on MARV. FIGS.11A and 11B depict charts summarizing the ability of compositions(oleandrin and PBI-05204) to inhibit Marburgvirus in Vero E6 cellsshortly after exposure to virus: FIG. 11A—2 hr post-infection; FIG.11B—24 hr post-infection. When the antiviral composition is administeredwithin two hours (or within up to 12 hours) after viral infection, theviral titre antiviral composition provides effective treatment andreduces the MARV viral titre. Even after 24 hours, the viral compositionis effective; however, its efficacy is lower as time after initial viralinfection increases.

Given that the antiviral activity of the composition herein is reducedfor a single generation of virus-infected cells, e.g. within 24 hourspost-infection, we evaluated whether the antiviral composition iscapable of inhibiting viral propagation, meaning inhibiting productionof infectious progeny. Vero E6 cells were infected with EBOV or MARV inthe presence of oleandrin or PBI-05204 and incubated for 48 hr.Supernatants from infected cell cultures were passaged onto fresh VeroE6 cells, incubated for 1 hr, then discarded. Cells containing passagedsupernatant were incubated for 48 hr. Cells infected with EBOV (B) orMARV (C) were evaluated as described herein. Control infection rateswere 66% for EBOV and 67% for MARV. The antiviral composition of theinvention inhibited production of infectious progeny.

Accordingly, the antiviral composition of the invention: a) can beadministered prophylactically before viral infection to inhibit viralinfection after exposure to virus; b) can be administered after viralinfection to inhibit or reduce viral replication and production ofinfectious progeny; or c) a combination of a) and b).

Antiviral activity of the antiviral composition against Togaviridaealphavirus was evaluated using VEE virus and WEE virus in Vero E6 cells.FIGS. 13A and 13B depict charts summarizing the in vitro dose responseantiviral activity of various compositions (oleandrin, digoxin andPBI-05204) against Venezuelen Equine Encephalomyelits virus (FIG. 13A)and Western Equine Encephalomyelitis virus (FIG. 13B) in Vero E6 cells.Vero E6 cells were infected with Venezuelan equine encephalitis virus(FIG. 13A, MOI=0.01) or Western equine encephalitis virus (FIG. 13B,MOI=0.1) for 18 hr in the presence or absence of indicated compounds.Infected cells were detected as before and enumerated on an Operetta.The antiviral composition of the invention was found to be efficacious.

Accordingly, the invention provides a method of treating a viralinfection, caused by a Filoviridae family virus, Flaviviridae familyvirus (Flavivirus genus), Deltaretrovirus genus virus, or Togaviridaefamily virus, in a subject or host cell, the method comprisingadministering an effective amount of the antiviral composition, therebyexposing the virus to the antiviral composition and treating said viralinfection.

We evaluated use of oleandrin and the extract described herein for thetreatment of HTLV-1 (human T-cell leukemia virus type-1; an envelopedretrovirus; Deltaretrovirus genus) infection. To determine whether thepurified oleandrin compound, or an extract of N. oleander, could inhibitHTLV-1 proviral replication and/or the production and release ofp19^(Gag)-containing virus particles, the virus-producingHTLV-1-transformed SLB1 lymphoma T-cell-line was treated with increasingconcentrations of oleandrin or a N. oleander extract, or the sterilevehicle control (20% DMSO in MilliQ-treated ddH₂O) and then incubatedfor 72 hrs at 37° C. under 10% CO₂. The cells were later pelleted bycentrifugation and the relative levels of extracellularp19^(Gag)-containing virus particles released into the culturesupernatants were quantified by performing Anti-HTLV-1 p19^(Gag) ELISAs(Zeptometrix).

FIG. 14 depicts data for quantitation of HTLV-1 p19^(Gag) expressed byHTLV-1+ SLB1 lymphoma T-cell-line treated for 72 hrs with the vehiclecontrol (1.5 μl, 7.5 μl, or 15 μl), or increasing concentrations (10μg/ml, 50 μg/ml, and 100 μg/ml) of the oleandrin compound or an extractof N. oleander (Example 19 and 20). Viral replication and the release ofextracellular particles into the culture supernatants were quantified byperforming Anti-HTLV-1 p19^(Gag) ELISAs (Zeptometrix). Oleandrin doesnot significantly inhibit HTLV-1 replication or the release ofnewly-synthesized virus particles. We determined that neither theextract nor oleandrin alone significantly inhibit viral replication orthe release of p19^(g)-containing particles into the supernatants of thecultures. We, thus, expected no further antiviral activity; however, weunexpectedly found that the collected virus particles from treated cellsexhibited reduced infectivity on primary human peripheral bloodmononuclear cells (huPBMCs). Unlike HIV-1, extracellular HTLV-1particles are poorly infectious and viral transmission typically occursvia direct intercellular interactions across a virological synapse.

The invention thus provides a method of producing HTLV-1 virus particleswith reduced infectivity, the method comprising treating HTLV-1 virusparticles with the antiviral composition of the invention to providesaid HTLV-1 virus particles with reduced infectivity.

To ensure that the antiviral activity observed was not an artifact dueto potential cytotoxicity of the antiviral composition to HTLV-1+ SLB1lymphoblast, we then assessed the cytotoxicity of the differentdilutions of the purified oleandrin compound and N. oleander extract intreated HTLV-1+ SLB1 lymphoblast cultures (Example 21). SLB1 T-cellswere treated with increasing concentrations (10, 50, and 100 μg/ml) ofoleandrin or a N. oleander extract for 72 hrs as described herein. As anegative control, the cells were also treated with increasing amounts(1.5, 7.5, and 15 μl) of the vehicle solution which corresponded to thevolumes used in the drug-treated cultures. Cyclophosphamide (50 μM;Sigma-Aldrich)-treated cells were included as a positive control forapoptosis. Then, the samples were washed and stained with Annexin V-FITCand propidium iodide (PI) and analyzed by confocalfluorescence-microscopy. The relative percentages of Annexin V-FITCand/or PI-positive cells were quantified by fluorescence-microscopy andcounting triplicate visual fields using a 20× objective lens.

The results (FIG. 15 and FIGS. 16A-16F) indicate that the lowestconcentration (10 μg/ml) of oleandrin and the N. oleander extract didnot induce significant cytotoxicity/apoptosis. However, the higherconcentrations (about 50 and about 100 μg/ml) of the crude phytoextractinduced notably more apoptosis than did the oleandrin compound. This isconsistent with the fact that oleandrin represents about 1.23% of the N.oleander extract. The cytotoxicity caused by oleandrin was notsignificantly higher than the Vehicle control in treated HTLV-1+ SLB1cells.

We then investigated whether oleandrin or a N. oleander extract couldinhibit virus transmission from a Green Fluorescent Protein(GFP)-expressing HTLV-1+ lymphoma T-cell-line to huPBMCs in co-cultureassays (Example 20). For these studies, HTLV-1+ SLB1 lymphoma T-cellswere treated with increasing concentrations of either the oleandrincompound or N. oleander extract, or the Vehicle control for 72 hrs in96-well microtiter plates, and then the virus-containing supernatantswere collected and used to directly infect primary cultured, humanperipheral blood mononuclear cells (huPBMCs) in vitro. Following 72 hrs,the relative levels of extracellular p19^(Gag)-containing virusparticles released into the culture supernatants, as a result of directinfection, were quantified by performing Anti-HTLV-1 p19^(Gag) ELISAs.

The HTLV-1+ SLB1 lymphoma T-cell-line was treated with the Vehiclecontrol, or increasing concentrations (10 μg/ml, 50 μg/ml, and 100μg/ml) of the N. oleander extract or oleandrin compound for 72 hrs andthen the virus-containing supernatants were collected and used todirectly infect primary huPBMCs. The vehicle control, N. oleanderextract, or oleandrin were also included in the culture media for thehuPBMCs. After 72 hrs, the culture supernatants were collected and therelative amounts of extracellular virus particles produced werequantified by performing Anti-HTLV-1 p19^(Gag) ELISAs.

The data (FIG. 17) indicate that the even lowest concentration (10μg/ml) of both oleandrin and the N. oleander extract inhibited theinfectivity of newly-synthesized p19^(Gag-)containing virus particlesreleased into the culture supernatants of treated cells, relative to acomparable amount of the vehicle control. Both oleandrin and the crudephytoextract inhibited the formation of virological synapses and thetransmission of HTLV-1 in vitro. Extracellular virus particles producedby oleandrin-treated HTLV-1+ lymphoma T-cells exhibit reducedinfectivity on primary huPBMCs. Importantly, oleandrin exhibitsantiviral activity against enveloped viruses by reducing theincorporation of the envelope glycoprotein into mature particles, whichrepresents a unique stage of the retroviral infection cycle.

To ensure that the antiviral activity observed was not an artifact dueto potential cytotoxicity of the antiviral composition to treatedhuPBMCs, we also investigated (Example 21) the cytotoxicity of purifiedoleandrin and the N. oleander extract, compared to the vehicle negativecontrol, in treated huPBMCs. Primary buffy-coat huPBMCs were isolatedand stimulated with phytohemagglutinin (PHA) and cultured in thepresence of recombinant human interleukin-2 (hIL-2). The cells were thentreated for 72 hrs with increasing concentrations of oleandrin or a N.oleander extract, or with increasing volumes of the Vehicle. The sampleswere subsequently stained with Annexin V-FITC and PI and the relativepercentages of apoptotic (i.e., Annexin V-FITC and/or PI-positive) cellsper field were quantified by confocal fluorescence-microscopy andcounting in-triplicate.

Cytotoxic effects of the Vehicle control, N. oleander extract, and theoleandrin compound were assessed by treating primary huPBMCs for 72 hrs,and then the cultures were stained with Annexin V-FITC and PI. Therelative percentages of apoptotic (i.e., Annexin V-FITC and/orPI-positive) cells were quantified by fluorescence-microscopy andcounting triplicate visual fields using a 20× objective lens. The totalnumbers of cells were determined using DIC phase-contrast microscopy.Cyclophosphamide (50 μM)-treated cells were included as a positivecontrol for apoptosis. NA indicates the number of cells in this samplewas too low for accurate assessment due to higher toxicity.

The data (FIG. 18) indicate oleandrin exhibited moderate cytotoxicity(e.g., 35-37% at the lowest concentration) in huPBMCs as compared to thevehicle control. By contrast, the N. oleander extract was significantlycytotoxic and induced high levels of programmed cell-death even at thelowest concentration. The huPBMCs were somewhat more sensitive topurified oleandrin than the HTLV-1+ SLB1 lymphoblasts; however, thehuPBMCs were drastically more sensitive to the crude N. oleander extractwhich also contains other cytotoxic compounds such as the triterpenesdescribed herein.

We also investigated (Example 22) whether oleandrin or the N. oleanderextract could interfere with the transmission of HTLV-1 particles totarget huPBMCs in co-culture experiments. For these studies, thevirus-producing HTLV-1+ SLB1 T-cell-line was treated with mitomycin Cand then with increasing amounts of oleandrin, N. oleander extract, orthe Vehicle control for either 15 min or 3 hrs. The SLB1 cells werewashed 2× with serum-free medium and equivalent numbers of huPBMCs werethen added to each well, and the samples were co-cultured for 72 hrs incomplete medium at 37° C. under 10% CO₂ in a humidified incubator. Therelative intercellular transmission of HTLV-1 was assessed by performingAnti-HTLV-1 p19^(Gag) ELISAs to measure the levels of extracellularvirus released into the culture supernatants.

Primary huPBMCs were co-cultured with mitomycin C-treated HTLV-1+ SLB1lymphoma T-cells which were pre-treated for either 15 min or 3 hrs withthe Vehicle control, or increasing concentrations (10 μg/ml, 50 μg/ml,and 100 μg/ml) of the N. oleander extract or oleandrin compound. Thevehicle control, extract, and compound were also present in theco-culture media. After 72 hrs, the supernatants were collected, and theamounts of extracellular virus particles released were quantified byperforming Anti-HTLV-1 p19^(Gag) ELISAs.

The results depicted in FIG. 19 demonstrate that both oleandrin and theN. oleander extract inhibited the transmission of HTLV-1 as compared tothe vehicle control; although, there were no differences observedbetween the 15 min and 3 hrs of pre-treatment of the HTLV-1+ SLB1 cells

We also investigated whether oleandrin inhibits virologicalsynapse-formation and the transmission of HTLV-1 in co-culture assays(Example 22). A GFP-expressing HTLV-1+ SLB1 T-cell-line was generated bytransducing SLB1 lymphoma T-cells with a pLenti-6.2/V5-DEST-GFP vectorwith selection on blasticidin (5 μg/ml; Life Technologies) for twoweeks. The GFP-positive clones were screened by fluorescence-microscopy(FIG. 20 top panels) and immunoblotting (FIG. 20 lower panels) andexpanded and repeatedly passaged. The DIC phase-contrast image isprovided for comparison.

The formation of virological synapses between huPBMCs and the mitomycinC-treated HTLV-1+ SLB1/pLenti-GFP lymphoblasts (green cells) that hadbeen pre-treated for 3 hrs with the Vehicle control or increasingamounts (10 μg/ml, 50 μg/ml, and 100 μg/ml) of the N. oleander extractor oleandrin compound were visualized by fluorescence-microscopy (FIG.21). Virus transmission was assessed by quantifying the relativepercentages of infected (i.e., HTLV-1 gp21-positive, red) huPBMCs(GFP-negative) in 20 visual fields (n=20) by fluorescence-microscopyusing a 20× objective lens (see arrows in the Vehicle control panels).The fluorescence-microscopy data was quantified (FIG. 22). The dataconfirm that the antiviral composition inhibits virologicalsynapse-formation and the transmission of HTLV-1 in co-culture assays.

The invention, thus, also provides a method of inhibiting (reducing) theinfectivity of HTLV-1 particles released into the culture supernatantsof treated cells and also reducing the intercellular transmission ofHTLV-1 by inhibiting the Env-dependent formation of virologicalsynapses, the method comprising treating virus-infected cells (in vitroor in vivo) with an effective amount of the antiviral composition.

Antiviral activity of the compositions herein was evaluated againstrhinovirus infection. Rhinovirus is of the Picomaviridae family andEnterovirus genus. It is not enveloped and is an ss-RNA virus of (+)polarity. Oleandrin was found to be inactive against rhinovirus in theconcentrations and assays employed herein, because it did not inhibitviral replication.

PBI-05204 (as described herein and in U.S. Pat. No. 8,187,644 B2 toAddington, which issued May 29, 2012, U.S. Pat. No. 7,402,325 B2 toAddington, which issued Jul. 22, 2008, U.S. Pat. No. 8,394,434 B2 toAddington et al, which issued Mar. 12, 2013, the entire disclosures ofwhich are hereby incorporated by reference) comprises cardiac glycoside(oleandrin, OL) and triterpenes (oleanolic acid (OA), ursolic acid (UA)and betulinic acid (BA)) as the primary pharmacologically activecomponents. The molar ratio of OL to total triterpene is about1:(10-96). The molar ratio of OA:UA:BA is about 7.8:7.4:1. Thecombination of OA, UA and BA in PBI-05204 increases the antiviralactivity of oleandrin when compared on an OL equimolar basis. PBI-04711is a fraction of PBI-05204, but it does not contain cardiac glycoside(OL). The molar ratio of OA:UA:BA in PBI-04711 is about 3:2.2:1.PBI-04711 also possesses antiviral activity. Accordingly, an antiviralcomposition comprising OL, OA, UA, and BA is more efficacious than acomposition comprising OL as the sole active ingredient based upon anequimolar content of OL. In some embodiments, the molar ratios of theindividual triterpenes to oleandrin range as follows: about 2-8(OA):about 2-8 (UA):about 0.1-1 (BA):about 0.5-1.5 (OL); or about 3-6(OA):about 3-6 (UA):about 0.3-8 (BA):about 0.7-1.2 (OL); or about 4-5(OA):about 4-5 (UA):about 0.4-0.7 (BA):about 0.9-1.1 (OL); or about 4.6(OA):about 4.4 (UA):about 0.6 (BA):about 1 (OL).

Antiviral compositions comprising oleandrin as the sole antiviral agentare within the scope of the invention.

Antiviral compositions comprising oleandrin and plural triterpenes asthe antiviral agents are within the scope of the invention. In someembodiments, the antiviral composition comprises oleandrin, oleanolicacid (free acid, salt, derivative or prodrug thereof), ursolic acid(free acid, salt, derivative or prodrug thereof), and betulinic acid(free acid, salt, derivative or prodrug thereof). The molar ratios ofthe compounds is as described herein.

Antiviral compositions comprising plural triterpenes as the primaryactive ingredients (meaning excluding steroid, cardiac glycoside andpharmacologically active components) are also within the scope of theinvention. As noted above, PBI-04711 comprises OA, UA and BA as theprimary active ingredients, and it exhibits antiviral activity. In someembodiments, a triterpene-based antiviral composition comprises OA, UAand BA, each of which is independently selected upon each occurrencefrom its free acid form, salt form, deuterated form and derivative form.

PBI-01011 is an improved triterpene-based antiviral compositioncomprising OA, UA and BA, wherein the molar ratio of OA:UA:BA is about9-12:up to about 2:up to about 2, or about 10:about 1:about 1, or about9-12:about 0.1-2:about 0.1-2, or about 9-11:about 0.5-1.5:about 0.5-1.5,or about 9.5-10.5:about 0.75-1.25:about 0.75-1.25, or about9.5-10.5:about 0.8-1.2:about 0.8-1.2, or about 9.75-10.5:about0.9-1.1:about 0.9-1.1.

In some embodiments, an antiviral composition comprises at leastoleanolic acid (free acid, salt, derivative or prodrug thereof) andursolic acid (free acid, salt, derivative or prodrug thereof) present ata molar ratio of OA to UA as described herein. OA is present in largemolar excess over UA.

In some embodiments, an antiviral composition comprises at leastoleanolic acid (free acid, salt, derivative or prodrug thereof) andbetulinic acid (free acid, salt, derivative or prodrug thereof) presentat a molar ratio of OA to BA as described herein. OA is present in largemolar excess over BA.

In some embodiments, an antiviral composition comprises at leastoleanolic acid (free acid, salt, derivative or prodrug thereof), ursolicacid (free acid, salt, derivative or prodrug thereof), and betulinicacid (free acid, salt, derivative or prodrug thereof) present at a molarratio of OA to UA to BA as described herein. OA is present in largemolar excess over both UA and BA.

In some embodiments, a triterpene-based antiviral composition excludescardiac glycoside.

In general, a subject having Filoviridae infection, Flaviviridaeinfection (Flavivirus genus), Deltaretrovirus genus, or Togaviridaeinfection is treated as follows. The subject is evaluated to determinewhether said subject is infected with said virus. Administration ofantiviral composition is indicated. Initial doses of antiviralcomposition are administered to the subject according to a prescribeddosing regimen for a period of time (a treatment period). The subject'sclinical response and level of therapeutic response are determinedperiodically. If the level of therapeutic response is too low at onedose, then the dose is escalated according to a predetermine doseescalation schedule until the desired level of therapeutic response inthe subject is achieved. Treatment of the subject with antiviralcomposition is continued as needed. The dose or dosing regimen can beadjusted as needed until the patient reaches the desired clinicalendpoint(s) such as cessation of the infection itself, reduction ininfection-associated symptoms, and/or a reduction in the progression ofthe infection.

If a clinician intends to treat a subject having viral infection with acombination of a antiviral composition and one or more other therapeuticagents, and it is known that the viral infection, which the subject has,is at least partially therapeutically responsive to treatment with saidone or more other therapeutic agents, then the present method inventioncomprises: administering to the subject in need thereof atherapeutically relevant dose of antiviral composition and atherapeutically relevant dose of said one or more other therapeuticagents, wherein the antiviral composition is administered according to afirst dosing regimen and the one or more other therapeutic agents isadministered according to a second dosing regimen. In some embodiments,the first and second dosing regimens are the same. In some embodiments,the first and second dosing regimens are different.

The antiviral composition(s) of the invention can be administered asprimary antiviral therapy, adjunct antiviral therapy, or co-antiviraltherapy. Methods of the invention include separate administration orcoadministration of the antiviral composition with at least one otherknown antiviral composition, meaning the antiviral composition of theinvention can be administered before, during or after administration ofa known antiviral composition (compound(s)) or of a composition fortreating symptoms associated with the viral infection. For example,medications used to treat inflammation, vomiting, nausea, headache,fever, diarrhea, nausea, hives, conjunctivitis, malaise, muscle pain,joint pain, seizure, or paralysis can be administered with or separatelyfrom the antiviral composition of the invention.

The one or more other therapeutic agents can be administered at dosesand according to dosing regimens that are clinician-recognized as beingtherapeutically effective or at doses that are clinician-recognized asbeing sub-therapeutically effective. The clinical benefit and/ortherapeutic effect provided by administration of a combination ofantiviral composition and one or more other therapeutic can be additiveor synergistic, such level of benefit or effect being determined bycomparison of administration of the combination to administration of theindividual antiviral composition component(s) and one or more othertherapeutic agents. The one or more other therapeutic agents can beadministered at doses and according to dosing regimens as suggested ordescribed by the Food and Drug Administration, World HealthOrganization, European Medicines Agency (E.M.E.A.), Therapeutic GoodsAdministration (TGA, Australia), Pan American Health Organization(PAHO), Medicines and Medical Devices Safety Authority (Medsafe, NewZealand) or the various Ministries of Health worldwide.

Exemplary other therapeutic agents that can be included in the antiviralcomposition of the invention for the treatment of HTLV-1 virus infectioninclude antiretroviral agent, interferon alpha (IFN-a), zidovudine,lamivudine, cyclosporine A, CHOP with arsenic trioxide, sodiumvalproate, methotrexate, azathioprine, one or more symptom alleviatingdrug(s), steroid sparing drug, corticosteroid, cyclophosphamide, andcombinations thereof. Therapies studied include plasmapheresis andradiation.

Example 5 provides an exemplary procedure for the treatment of Zikavirusinfection in a mammal. Example 12 provides an exemplary procedure forthe treatment of Filovirus infection (Ebolavirus, Marburgvirus) in amammal. Example 13 provides an exemplary procedure for the treatment ofFlavivirus infection (Yellow Fever, Dengue Fever, JapaneseEnchephalitis, West Nile Viruses, Zikavirus, Tick-borne Encephalitis,Kyasanur Forest Disease, Alkhurma Disease, Omsk Hemorrhagic Fever,Powassan virus infection) in a mammal. Example 25 provides an exemplaryprocedure for the treatment of Deltaretrovirus genus (HTLV-1) infection.

The antiviral compound(s) (triterpene(s), cardiac glycoside(s), etc.)present in the pharmaceutical composition can be present in theirunmodified form, salt form, derivative form or a combination thereof. Asused herein, the term “derivative” is taken to mean: a) a chemicalsubstance that is related structurally to a first chemical substance andtheoretically derivable from it; b) a compound that is formed from asimilar first compound or a compound that can be imagined to arise fromanother first compound, if one atom of the first compound is replacedwith another atom or group of atoms; c) a compound derived or obtainedfrom a parent compound and containing essential elements of the parentcompound; or d) a chemical compound that may be produced from firstcompound of similar structure in one or more steps. For example, aderivative may include a deuterated form, oxidized form, dehydrated,unsaturated, polymer conjugated or glycosilated form thereof or mayinclude an ester, amide, lactone, homolog, ether, thioether, cyano,amino, alkylamino, sulfhydryl, heterocyclic, heterocyclic ring-fused,polymerized, pegylated, benzylidenyl, triazolyl, piperazinyl ordeuterated form thereof.

As used herein, the term “oleandrin” is taken to mean all known forms ofoleandrin unless otherwise specified. Oleandrin can be present inracemic, optically pure or optically enriched form. Nerium oleanderplant material can be obtained, for example, from commercial plantsuppliers such as Aldridge Nursery, Atascosa, Tex.

The supercritical fluid (SCF) extract can be prepared as detailed inU.S. Pat. Nos. 7,402,325, 8,394,434, 8,187,644, or PCT InternationalPublication No. WP 2007/016176 A2, the entire disclosures of which arehereby incorporated by reference. Extraction can be conducted withsupercritical carbon dioxide in the presence or absence of a modifier(organic solvent) such as ethanol.

Other extracts containing cardiac glycoside, especially oleandrin, canbe prepared by various different processes. An extract can be preparedaccording to the process developed by Dr. Huseyin Ziya Ozel (U.S. Pat.No. 5,135,745) describes a procedure for the preparation of a hot waterextract. The aqueous extract reportedly contains several polysaccharideswith molecular weights varying from 2KD to 30KD, oleandrin andoleandrigenin, odoroside and neritaloside. The polysaccharidesreportedly include acidic homopolygalacturonans or arabinogalaturonans.U.S. Pat. No. 5,869,060 to Selvaraj et al. discloses hot water extractsof Nerium species and methods of production thereof, e.g. Example 2. Theresultant extract can then be lyophilized to produce a powder. U.S. Pat.No. 6,565,897 (U.S. Pregrant Publication No. 20020114852 and PCTInternational Publication No. WO 2000/016793 to Selvaraj et al.)discloses a hot-water extraction process for the preparation of asubstantially sterile extract. Erdemoglu et al. (J. Ethnopharmacol.(2003) November 89(1), 123-129) discloses results for the comparison ofaqueous and ethanolic extracts of plants, including Nerium oleander,based upon their anti-nociceptive and anti-inflammatory activities.Organic solvent extracts of Nerium oleander are disclosed by Adome etal. (Afr. Health Sci. (2003) August 3(2), 77-86; ethanolic extract),el-Shazly et al. (J. Egypt Soc. Parasitol. (1996), August 26(2),461-473; ethanolic extract), Begum et al. (Phytochemistry (1999)February 50(3), 435-438; methanolic extract), Zia et al. (JEthnolpharmacol. (1995) November 49(1), 33-39; methanolic extract), andVlasenko et al. (Farmatsiia. (1972) September-October 21(5), 46-47;alcoholic extract). U.S. Pregrant Patent Application Publication No.20040247660 to Singh et al. discloses the preparation of a proteinstabilized liposomal formulation of oleandrin for use in the treatmentof cancer. U.S. Pregrant Patent Application Publication No. 20050026849to Singh et al. discloses a water soluble formulation of oleandrincontaining a cyclodextrin. U.S. Pregrant Patent Application PublicationNo. 20040082521 to Singh et al. discloses the preparation of proteinstabilized nanoparticle formulations of oleandrin from the hot-waterextract.

The extracts also differ in their polysaccharide and carbohydratecontent. The hot water extract contains 407.3 glucose equivalent unitsof carbohydrate relative to a standard curve prepared with glucose whileanalysis of the SCF CO₂ extract found carbohydrate levels that werefound in very low levels that were below the limit of quantitation. Theamount of carbohydrate in the hot water extract of Nerium oleander was,however, at least 100-fold greater than that in the SCF CO₂ extract. Thepolysaccharide content of the SCF extract can be 0%, <0.5%, <0.1%,<0.05%, or <0.01% wt. In some embodiments, the SCF extract excludespolysaccharide obtained during extraction of the plant mass.

Carbohydrate content (μg glucose equivalents/mg of plant Nerium oleanderpreparation extract) Hot water extract 407.3 ± 6.3 SCF CO₂ extract BLQ(below limit of quantitation)

The partial compositions of the SCF CO₂ extract and hot water extractwere determined by DART TOF-MS (Direct Analysis in Real Time Time ofFlight Mass Spectrometry) on a JEOL AccuTOF-DART mass spectrometer (JEOLUSA, Peabody, Mass., USA).

The SCF extract of Nerium species or Thevetia species is a mixture ofpharmacologically active compounds, such as oleandrin and triterpenes.The extract obtained by the SCF process is a substantiallywater-insoluble, viscous semi-solid (after solvent is removed) atambient temperature. The SCF extract comprises many different componentspossessing a variety of different ranges of water solubility. Theextract from a supercritical fluid process contains by weight atheoretical range of 0.9% to 2.5% wt of oleandrin or 1.7% to 2.1% wt ofoleandrin or 1.7% to 2.0% wt of oleandrin. SCF extracts comprisingvarying amount of oleandrin have been obtained. In one embodiment, theSCF extract comprises about 2% by wt. of oleandrin. The SCF extractcontains a 3-10 fold higher concentration of oleandrin than thehot-water extract. This was confirmed by both HPLC as well as LC/MS/MS(tandem mass spectrometry) analyses.

The SCF extract comprises oleandrin and the triterpenes oleanolic acid,betulinic acid and ursolic acid and optionally other components asdescribed herein. The content of oleandrin and the triterpenes can varyfrom batch to batch; however, the degree of variation is not excessive.For example, a batch of SCF extract (PBI-05204) was analyzed for thesefour components and found to contain the following approximate amountsof each.

Oleandrin Oleanolic acid Ursolic acid Betulinic acid Content of 20 73 699.4 component (mg/g of SCF extract) Content of 2 7.3 6.9 0.94 component(% wt WRT g of SCT extract) Content of 34.7 160 152 20.6 component(mmole/g of SCF extract) Molar ratio of 1 4.6 4.4 0.6 component WRToleandrin WRT denotes “with respect to”.

The content of the individual components may vary by ±25%, ±20%, ±15%,±10% or ±5% relative to the values indicated. Accordingly, the contentof oleandrin in the SCF extract would be in the range of 20 mg±5 mg(which is ±25% of 20 mg) per mg of SCF extract.

Oleandrin, oleanolic acid, ursolic acid, betulinic acid and derivativesthereof can also be purchased from Sigma-Aldrich (www.sigmaaldrich.com;St. Louis, Mo., USA).

As used herein, the individually named triterpenes can independently beselected upon each occurrence in their native (unmodified, free acid)form, in their salt form, in derivative form, prodrug form, or acombination thereof. Compositions containing and methods employingdeuterated forms of the triterpenes are also within the scope of theinvention.

Oleanolic acid derivatives, prodrugs and salts are disclosed in US20150011627 A1 to Gribble et al. which published Jan. 8, 2015, US20140343108 A1 to Rong et al which published Nov. 20, 2014, US20140343064 A1 to Xu et al. which published Nov. 20, 2014, US20140179928 A1 to Anderson et al. which published Jun. 26, 2014, US20140100227 A1 to Bender et al. which published Apr. 10, 2014, US20140088188 A1 to Jiang et al. which published Mar. 27, 2014, US20140088163 A1 to Jiang et al. which published Mar. 27, 2014, US20140066408 A1 to Jiang et al. which published Mar. 6, 2014, US20130317007 A1 to Anderson et al. which published Nov. 28, 2013, US20130303607 A1 to Gribble et al. which published Nov. 14, 2013, US20120245374 to Anderson et al. which published Sep. 27, 2012, US20120238767 A1 to Jiang et al. which published Sep. 20, 2012, US20120237629 A1 to Shode et al. which published Sep. 20, 2012, US20120214814 A1 to Anderson et al. which published Aug. 23, 2012, US20120165279 A1 to Lee et al. which published Jun. 28, 2012, US20110294752 A1 to Arntzen et al. which published Dec. 1, 2011, US20110091398 A1 to Majeed et al. which published Apr. 21, 2011, US20100189824 A1 to Amtzen et al. which published Jul. 29, 2010, US20100048911 A1 to Jiang et al. which published Feb. 25, 2010, and US20060073222 A1 to Arntzen et al. which published Apr. 6, 2006, theentire disclosures of which are hereby incorporated by reference.

Ursolic acid derivatives, prodrugs and salts are disclosed in US20150011627 A1 to Gribble et al. which published Jan. 8, 2015, US20130303607 A1 to Gribble et al. which published Nov. 14, 2013, US20150218206 A1 to Yoon et al. which published Aug. 6, 2015, U.S. Pat.No. 6,824,811 to Fritsche et al. which issued Nov. 30, 2004, U.S. Pat.No. 7,718,635 to Ochiai et al. which issued May 8, 2010, U.S. Pat. No.8,729,055 to Lin et al. which issued May 20, 2014, and U.S. Pat. No.9,120,839 to Yoon et al. which issued Sep. 1, 2015, the entiredisclosures of which are hereby incorporated by reference.

Betulinic acid derivatives, prodrugs and salts are disclosed in US20150011627 A1 to Gribble et al. which published Jan. 8, 2015, US20130303607 A1 to Gribble et al. which published Nov. 14, 2013, US20120237629 A1 to Shode et al. which published Sep. 20, 2012, US20170204133 A1 to Regueiro-Ren et al. which published Jul. 20, 2017, US20170096446 A1 to Nitz et al. which published Apr. 6, 2017, US20150337004 A1 to Parthasaradhi Reddy et al. which published Nov. 26,2015, US 20150119373 A1 to Parthasaradhi Reddy et al. which publishedApr. 30, 2015, US 20140296546 A1 to Yan et al. which published Oct. 2,2014, US 20140243298 A1 to Swidorski et al. which published Aug. 28,2014, US 20140221328 A1 to Parthasaradhi Reddy et al. which publishedAug. 7, 2014, US 20140066416 A1 tp Leunis et al. which published Mar. 6,2014, US 20130065868 A1 to Durst et al. which published Mar. 14, 2013,US 20130029954 A1 to Regueiro-Ren et al. which published Jan. 31, 2013,US 20120302530 A1 to Zhang et al. which published Nov. 29, 2012, US20120214775 A1 to Power et al. which published Aug. 23, 2012, US20120101149 A1 to Honda et al. which published Apr. 26, 2012, US20110224182 to Bullock et al. which published Sep. 15, 2011, US20110313191 A1 to Hemp et al. which published Dec. 22, 2011, US20110224159 A1 to Pichette et al. which published Sep. 15, 2011, US20110218204 to Parthasaradhi Reddy et al. which published Sep. 8, 2011,US 20090203661 A1 to Safe et al. which published Aug. 13, 2009, US20090131714 A1 to Krasutsky et al. which published May 21, 2009, US20090076290 to Krasutsky et al. which published Mar. 19, 2009, US20090068257 A1 to Leunis et al. which published Mar. 12, 2009, US20080293682 to Mukherjee et al. which published Nov. 27, 2008, US20070072835 A1 to Pezzuto et al. which published Mar. 29, 2007, US20060252733 A1 to Jansen et al. which published Nov. 9, 2006, and US2006025274 A1 to O'Neill et al. which published Nov. 9, 2006, the entiredisclosures of which are hereby incorporated by reference.

The antiviral composition can be formulated in any suitablepharmaceutically acceptable dosage form. Parenteral, otic, ophthalmic,nasal, inhalable, buccal, sublingual, enteral, topical, oral, peroral,and injectable dosage forms are particularly useful. Particular dosageforms include a solid or liquid dosage forms. Exemplary suitable dosageforms include tablet, capsule, pill, caplet, troche, sache, solution,suspension, dispersion, vial, bag, bottle, injectable liquid, i.v.(intravenous), i.m. (intramuscular) or i.p. (intraperitoneal)administrable liquid and other such dosage forms known to the artisan ofordinary skill in the pharmaceutical sciences.

Suitable dosage forms containing the antiviral composition can beprepared by mixing the antiviral composition with pharmaceuticallyacceptable excipients as described herein or as described in Pi et al.(“Ursolic acid nanocrystals for dissolution rate and bioavailabilityenhancement: influence of different particle size” in Curr. Drug Deliv.(March 2016), 13(8), 1358-1366), Yang et al. (“Self-microemulsifyingdrug delivery system for improved oral bioavailability of oleanolicacid: design and evaluation” in Int. J. Nanomed. (2013), 8(1),2917-2926), Li et al. (Development and evaluation of optimized sucroseester stabilized oleanolic acid nanosuspensions prepared by wet ballmilling with design of experiments” in Biol. Pharm. Bull. (2014), 37(6),926-937), Zhang et al. (“Enhancement of oral bioavailability oftriterpene through lipid nanospheres: preparation, characterization, andabsorption evaluation” in J. Pharm. Sci. (June 2014), 103(6),1711-1719), Godugu et al. (“Approaches to improve the oralbioavailability and effects of novel anticancer drugs berberine andbetulinic acid” in PLoS One (March 2014), 9(3):e89919), Zhao et al.(“Preparation and characterization of betulin nanoparticles for oralhypoglycemic drug by antisolvent precipitation” in Drug Deliv.(September 2014), 21(6), 467-479), Yang et al. (“Physicochemicalproperties and oral bioavailability of ursolic acid nanoparticles usingsupercritical anti-solvent (SAS) process” in Food Chem. (May 2012),132(1), 319-325), Cao et al. (“Ethylene glycol-linked amino acid diesterprodrugs of oleanolic acid for PEPT1-mediated transport: synthesis,intestinal permeability and pharmacokinetics” in Mol. Pharm. (August2012), 9(8), 2127-2135), Li et al. (“Formulation, biological andpharmacokinetic studies of sucrose ester-stabilized nanosuspensions ofoleanolic acid” in Pharm. Res. (August 2011), 28(8), 2020-2033), Tong etal. (“Spray freeze drying with polyvinylpyrrolidone and sodium capratefor improved dissolution and oral bioavailablity of oleanolic acid, aBCS Class IV compound” in Int. J. Pharm. (February 2011), 404(1-2),148-158), Xi et al. (Formulation development and bioavailabilityevaluation of a self-nanoemulsified drug delivery system of oleanolicacid” in AAPS PharmSciTech (2009), 10(1), 172-182), Chen et al.(“Oleanolic acid nanosuspensions: preparation, in-vitro characterizationand enhanced hepatoprotective effect” in J. Pharm. Pharmacol. (February2005), 57(2), 259-264), the entire disclosures of which are herebyincorporated by reference.

Suitable dosage forms can also be made according to U.S. Pat. No.8,187,644 B2 to Addington, which issued May 29, 2012, U.S. Pat. No.7,402,325 B2 to Addington, which issued Jul. 22, 2008, U.S. Pat. No.8,394,434 B2 to Addington et al, which issued Mar. 12, 2013, the entiredisclosures of which are hereby incorporated by reference. Suitabledosage forms can also be made as described in Examples 13-15.

An effective amount or therapeutically relevant amount of antiviralcompound (cardiac glycoside, triterpene or combinations thereof) isspecifically contemplated. By the term “effective amount”, it isunderstood that a pharmaceutically effective amount is contemplated. Apharmaceutically effective amount is the amount or quantity of activeingredient which is enough for the required or desired therapeuticresponse, or in other words, the amount, which is sufficient to elicitan appreciable biological response when, administered to a patient. Theappreciable biological response may occur as a result of administrationof single or multiple doses of an active substance. A dose may compriseone or more dosage forms. It will be understood that the specific doselevel for any patient will depend upon a variety of factors includingthe indication being treated, severity of the indication, patienthealth, age, gender, weight, diet, pharmacological response, thespecific dosage form employed, and other such factors.

The desired dose for oral administration is up to 5 dosage formsalthough as few as one and as many as ten dosage forms may beadministered as a single dose. Exemplary dosage forms can contain0.01-100 mg or 0.01-100 microg of the antiviral composition per dosageform, for a total 0.1 to 500 mg (1 to 10 dose levels) per dose. Doseswill be administered according to dosing regimens that may bepredetermined and/or tailored to achieve specific therapeutic responseor clinical benefit in a subject.

The cardiac glycoside can be present in a dosage form in an amountsufficient to provide a subject with an initial dose of oleandrin ofabout 20 to about 100 microg, about 12 microg to about 300 microg, orabout 12 microg to about 120 microg. A dosage form can comprise about 20of oleandrin to about 100 microg, about 0.01 microg to about 100 mg orabout 0.01 microg to about 100 microg oleandrin, oleandrin extract orextract of Nerium oleander containing oleandrin.

The antiviral can be included in an oral dosage form. Some embodimentsof the dosage form are not enteric coated and release their charge ofantiviral composition within a period of 0.5 to 1 hours or less. Someembodiments of the dosage form are enteric coated and release theircharge of antiviral composition downstream of the stomach, such as fromthe jejunum, ileum, small intestine, and/or large intestine (colon).Enterically coated dosage forms will release antiviral composition intothe systemic circulation within 1-10 hr after oral administration.

The antiviral composition can be included in a rapid release, immediaterelease, controlled release, sustained release, prolonged release,extended release, burst release, continuous release, slow release, orpulsed release dosage form or in a dosage form that exhibits two or moreof those types of release. The release profile of antiviral compositionfrom the dosage form can be a zero order, pseudo-zero, first order,pseudo-first order or sigmoidal release profile. The plasmaconcentration profile for triterpene in a subject to which the antiviralcomposition is administered can exhibit one or more maxima.

Based on human clinical data it is anticipated that 50% to 75% of anadministered dose of oleandrin will be orally bioavailable thereforeproviding about 10 to about 20 microg, about 20 to about 40 microg,about 30 to about 50 microg, about 40 to about 60 microg, about 50 toabout 75 microg, about 75 to about 100 microg of oleandrin per dosageform. Given an average blood volume in adult humans of 5 liters, theanticipated oleandrin plasma concentration will be in the range of about0.05 to about 2 ng/ml, about 0.005 to about 10 ng/mL, about 0.005 toabout 8 ng/mL, about 0.01 to about 7 ng/mL, about 0.02 to about 7 ng/mL,about 0.03 to about 6 ng/mL, about 0.04 to about 5 ng/mL, or about 0.05to about 2.5 ng/mL. The recommended daily dose of oleandrin, present inthe SCF extract, is generally about 0.2 microg to about 4.5 microg/kgbody weight twice daily. The dose of oleandrin can be about 0.2 to about1 microg/kg body weight/day, about 0.5 to about 1.0 microg/kg bodyweight/day, about 0.75 to about 1.5 microg/kg body weight/day, about 1.5to about 2.52 microg/kg body weight/day, about 2.5 to about 3.0microg/kg body weight/day, about 3.0 to 4.0 microg/kg body weight/day orabout 3.5 to 4.5 microg oleandrin/kg body weight/day. The maximumtolerated dose of oleandrin can be about about 3.5 microg/kg bodyweight/day to about 4.0 microg/kg body weight/day. The minimum effectivedose can be about 0.5 microg/day, about 1 microg/day, about 1.5microg/day, about 1.8 microg/day, about 2 microg/day, or about 5microg/day.

The antiviral composition can be administered at low to high dose due tothe combination of triterpenes present and the molar ratio at which theyare present. A therapeutically effective dose for humans is about100-1000 mg or about 100-1000 microg of antiviral composition per Kg ofbody weight. Such a dose can be administered up to 10 times in a 24-hourperiod. Other suitable dosing ranges are specified below.

Oleanolic Ursolic Betulinic Oleandrin acid acid acid SuitableComposition (moles) (moles) (moles) (moles) dose A 0.5-1.5 4-6 — — 0.05to 0.5 mg/kg/day B 0.5-1.5 4-6 4-6 — 0.05 to 0.35 mg/kg/day C 0.5-1.54-6 4-6 0.1-1 0.05 to 0.22 (PBI-05204) mg/kg/day D 0.5-1.5 — 4-6 — 0.05to 0.4 mg/kg/day E 0.5-1.5 — — 0.1-1 0.05 to 0.4 mg/kg/day AA About 1 —— 0.3-0.7 0.05 to 0.4 mg/kg/day AB About 1 About 4.7 — — 0.05 to 0.5mg/kg/day AC About 1 About 4.7 About 4.5 — 0.05 to 0.4 mg/kg/day ADAbout 1 About 4.7 About 4.5 About 0.6 0.05 to 0.22 (PBI-05204) mg/kg/dayAE About 1 — About 4.5 — 0.05 to 0.4 mg/kg/day AF About 1 — — About 0.60.05 to 0.3 mg/kg/day All values are approximate, meaning “about” thespecified value.

It should be noted that a compound herein might possess one or morefunctions in a composition or formulation of the invention. For example,a compound might serve as both a surfactant and a water miscible solventor as both a surfactant and a water immiscible solvent.

A liquid composition can comprise one or more pharmaceuticallyacceptable liquid carriers. The liquid carrier can be an aqueous,non-aqueous, polar, non-polar, and/or organic carrier. Liquid carriersinclude, by way of example and without limitation, a water misciblesolvent, water immiscible solvent, water, buffer and mixtures thereof.

As used herein, the terms “water soluble solvent” or “water misciblesolvent”, which terms are used interchangeably, refer to an organicliquid which does not form a biphasic mixture with water or issufficiently soluble in water to provide an aqueous solvent mixturecontaining at least five percent of solvent without separation of liquidphases. The solvent is suitable for administration to humans or animals.Exemplary water soluble solvents include, by way of example and withoutlimitation, PEG (poly(ethylene glycol)), PEG 400 (poly(ethylene glycolhaving an approximate molecular weight of about 400), ethanol, acetone,alkanol, alcohol, ether, propylene glycol, glycerin, triacetin,poly(propylene glycol), PVP (poly(vinyl pyrrolidone)),dimethylsulfoxide, N,N-dimethylformamide, formamide,N,N-dimethylacetamide, pyridine, propanol, N-methylacetamide, butanol,soluphor (2-pyrrolidone), pharmasolve (N-methyl-2-pyrrolidone).

As used herein, the terms “water insoluble solvent” or “water immisciblesolvent”, which terms are used interchangeably, refer to an organicliquid which forms a biphasic mixture with water or provides a phaseseparation when the concentration of solvent in water exceeds fivepercent. The solvent is suitable for administration to humans oranimals. Exemplary water insoluble solvents include, by way of exampleand without limitation, medium/long chain triglycerides, oil, castoroil, corn oil, vitamin E, vitamin E derivative, oleic acid, fatty acid,olive oil, softisan 645 (Diglyceryl Caprylate/Caprate/Stearate/Hydroxystearate adipate), miglyol, captex (Captex 350: GlycerylTricaprylate/Caprate/Laurate triglyceride; Captex 355: GlycerylTricaprylate/Caprate triglyceride; Captex 355 EP/NF: GlycerylTricaprylate/Caprate medium chain triglyceride).

Suitable solvents are listed in the “International Conference onHarmonisation of Technical Requirements for Registration ofPharmaceuticals for Human Use (ICH) guidance for industry Q3CImpurities: Residual Solvents” (1997), which makes recommendations as towhat amounts of residual solvents are considered safe inpharmaceuticals. Exemplary solvents are listed as class 2 or class 3solvents. Class 3 solvents include, for example, acetic acid, acetone,anisole, 1-butanol, 2-butanol, butyl acetate, tert-butlymethyl ether,cumene, ethanol, ethyl ether, ethyl acetate, ethyl formate, formic acid,heptane, isobutyl acetate, isopropyl acetate, methyl acetate,methyl-1-butanol, methylethyl ketone, methylisobutyl ketone,2-methyl-1-propanol, pentane, 1-pentanol, 1-propanol, 2-propanol, orpropyl acetate.

Other materials that can be used as water immiscible solvents in theinvention include: Captex 100: Propylene Glycol Dicaprate; Captex 200:Propylene Glycol Dicaprylate/Dicaprate; Captex 200 P: Propylene GlycolDicaprylate/Dicaprate; Propylene Glycol Dicaprylocaprate; Captex 300:Glyceryl Tricaprylate/Caprate; Captex 300 EP/NF: GlycerylTricaprylate/Caprate Medium Chain Triglycerides; Captex 350: GlycerylTricaprylate/Caprate/Laurate; Captex 355: Glyceryl Tricaprylate/Caprate;Captex 355 EP/NF: Glyceryl Tricaprylate/Caprate Medium ChainTriglycerides; Captex 500: Triacetin; Captex 500 P: Triacetin(Pharmaceutical Grade); Captex 800: Propylene Glycol Di(2-Ethythexanoate); Captex 810 D: GlycerylTricaprylate/Caprate/Linoleate; Captex 1000: Glyceryl Tricaprate; CaptexCA: Medium Chain Triglycerides; Captex MCT-170: Medium ChainTriglycerides; Capmul GMO: Glyceryl Monooleate; Capmul GMO-50 EP/NF:Glyceryl Monooleate; Capmul MCM: Medium Chain Mono- & Diglycerides;Capmul MCM C8: Glyceryl Monocaprylate; Capmul MCM C10: GlycerylMonocaprate; Capmul PG-8: Propylene Glycol Monocaprylate; Capmul PG-12:Propylene Glycol Monolaurate; Caprol 10G100: Decaglycerol Decaoleate;Caprol 3GO: Triglycerol Monooleate; Caprol ET: Polyglycerol Ester ofMixed Fatty Acids; Caprol MPGO: Hexaglycerol Dioleate; Caprol PGE 860:Decaglycerol Mono-, Dioleate.

As used herein, a “surfactant” refers to a compound that comprises polaror charged hydrophilic moieties as well as non-polar hydrophobic(lipophilic) moieties; i.e., a surfactant is amphiphilic. The termsurfactant may refer to one or a mixture of compounds. A surfactant canbe a solubilizing agent, an emulsifying agent or a dispersing agent. Asurfactant can be hydrophilic or hydrophobic.

The hydrophilic surfactant can be any hydrophilic surfactant suitablefor use in pharmaceutical compositions. Such surfactants can be anionic,cationic, zwitterionic or non-ionic, although non-ionic hydrophilicsurfactants are presently preferred. As discussed above, these non-ionichydrophilic surfactants will generally have HLB values greater thanabout 10. Mixtures of hydrophilic surfactants are also within the scopeof the invention.

Similarly, the hydrophobic surfactant can be any hydrophobic surfactantsuitable for use in pharmaceutical compositions. In general, suitablehydrophobic surfactants will have an HLB value less than about 10.Mixtures of hydrophobic surfactants are also within the scope of theinvention.

Examples of additional suitable solubilizer include: alcohols andpolyols, such as ethanol, isopropanol, butanol, benzyl alcohol, ethyleneglycol, propylene glycol, butanediols and isomers thereof, glycerol,pentaerythritol, sorbitol, mannitol, transcutol, dimethyl isosorbide,polyethylene glycol, polypropylene glycol, polyvinylalcohol,hydroxypropyl methylcellulose and other cellulose derivatives,cyclodextrins and cyclodextrin derivatives; ethers of polyethyleneglycols having an average molecular weight of about 200 to about 6000,such as tetrahydrofurfuryl alcohol PEG ether (glycofurol, availablecommercially from BASF under the trade name Tetraglycol) or methoxy PEG(Union Carbide); amides, such as 2-pyrrolidone, 2-piperidone,caprolactam, N-alkylpyrrolidone, N-hydroxyalkylpyrrolidone,N-alkylpiperidone, N-alkylcaprolactam, dimethylacetamide, andpolyvinypyrrolidone; esters, such as ethyl propionate, tributylcitrate,acetyl triethylcitrate, acetyl tributyl citrate, triethylcitrate, ethyloleate, ethyl caprylate, ethyl butyrate, triacetin, propylene glycolmonoacetate, propylene glycol diacetate, caprolactone and isomersthereof, valerolactone and isomers thereof, butyrolactone and isomersthereof; and other solubilizers known in the art, such as dimethylacetamide, dimethyl isosorbide (Arlasolve DMI (ICI)), N-methylpyrrolidones (Pharmasolve (ISP)), monooctanoin, diethylene glycolnonoethyl ether (available from Gattefosse under the trade nameTranscutol), and water. Mixtures of solubilizers are also within thescope of the invention.

Except as indicated, compounds mentioned herein are readily availablefrom standard commercial sources.

Although not necessary, the composition or formulation may furthercomprise one or more chelating agents, one or more preservatives, one ormore antioxidants, one or more adsorbents, one or more acidifyingagents, one or more alkalizing agents, one or more antifoaming agents,one or more buffering agents, one or more colorants, one or moreelectrolytes, one or more salts, one or more stabilizers, one or moretonicity modifiers, one or more diluents, or a combination thereof.

The composition of the invention can also include oils such as fixedoils, peanut oil, sesame oil, cottonseed oil, corn oil and olive oil;fatty acids such as oleic acid, stearic acid and isostearic acid; andfatty acid esters such as ethyl oleate, isopropyl myristate, fatty acidglycerides and acetylated fatty acid glycerides. The composition canalso include alcohol such as ethanol, isopropanol, hexadecyl alcohol,glycerol and propylene glycol; glycerol ketals such as2,2-dimethyl-1,3-dioxolane-4-methanol; ethers such as poly(ethyleneglycol) 450; petroleum hydrocarbons such as mineral oil and petrolatum;water; a pharmaceutically suitable surfactant, suspending agent oremulsifying agent; or mixtures thereof.

It should be understood that the compounds used in the art ofpharmaceutical formulation generally serve a variety of functions orpurposes. Thus, if a compound named herein is mentioned only once or isused to define more than one term herein, its purpose or function shouldnot be construed as being limited solely to that named purpose(s) orfunction(s).

One or more of the components of the formulation can be present in itsfree base, free acid or pharmaceutically or analytically acceptable saltform. As used herein, “pharmaceutically or analytically acceptable salt”refers to a compound that has been modified by reacting it with an acidas needed to form an ionically bound pair. Examples of acceptable saltsinclude conventional non-toxic salts formed, for example, from non-toxicinorganic or organic acids. Suitable non-toxic salts include thosederived from inorganic acids such as hydrochloric, hydrobromic,sulfuric, sulfonic, sulfamic, phosphoric, nitric and others known tothose of ordinary skill in the art. The salts prepared from organicacids such as amino acids, acetic, propionic, succinic, glycolic,stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic,hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic,2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethanedisulfonic, oxalic, isethionic, and others known to those of ordinaryskill in the art. On the other hand, where the pharmacologically activeingredient possesses an acid functional group, a pharmaceuticallyacceptable base is added to form the pharmaceutically acceptable salt.Lists of other suitable salts are found in Remington's PharmaceuticalSciences, 17^(th); ed., Mack Publishing Company, Easton, Pa., 1985, p.1418, the relevant disclosure of which is hereby incorporated byreference.

The phrase “pharmaceutically acceptable” is employed herein to refer tothose compounds, materials, compositions, and/or dosage forms which are,within the scope of sound medical judgment, suitable for use in contactwith tissues of human beings and animals and without excessive toxicity,irritation, allergic response, or any other problem or complication,commensurate with a reasonable benefit/risk ratio.

A dosage form can be made by any conventional means known in thepharmaceutical industry. A liquid dosage form can be prepared byproviding at least one liquid carrier and antiviral composition in acontainer. One or more other excipients can be included in the liquiddosage form. A solid dosage form can be prepared by providing at leastone solid carrier and antiviral composition. One or more otherexcipients can be included in the solid dosage form.

A dosage form can be packaged using conventional packaging equipment andmaterials. It can be included in a pack, bottle, via, bag, syringe,envelope, packet, blister pack, box, ampoule, or other such container.

The composition of the invention can be included in any dosage form.Particular dosage forms include a solid or liquid dosage forms.Exemplary suitable dosage forms include tablet, capsule, pill, caplet,troche, sache, and other such dosage forms known to the artisan ofordinary skill in the pharmaceutical sciences.

In view of the above description and the examples below, one of ordinaryskill in the art will be able to practice the invention as claimedwithout undue experimentation. The foregoing will be better understoodwith reference to the following examples that detail certain proceduresfor the preparation of embodiments of the present invention. Allreferences made to these examples are for the purposes of illustration.The following examples should not be considered exhaustive, but merelyillustrative of only a few of the many embodiments contemplated by thepresent invention.

Example 1 Supercritical Fluid Extraction of Powdered Oleander LeavesMethod A. With Carbon Dioxide.

Powdered oleander leaves were prepared by harvesting, washing, anddrying oleander leaf material, then passing the oleander leaf materialthrough a comminuting and dehydrating apparatus such as those describedin U.S. Pat. Nos. 5,236,132, 5,598,979, 6,517,015, and 6,715,705. Theweight of the starting material used was 3.94 kg.

The starting material was combined with pure C02 at a pressure of 300bar (30 MPa, 4351 psi) and a temperature of 50° C. (122° F.) in anextractor device. A total of 197 kg of CO₂ was used, to give a solventto raw material ratio of 50:1. The mixture of CO₂ and raw material wasthen passed through a separator device, which changed the pressure andtemperature of the mixture and separated the extract from the carbondioxide.

The extract (65 g) was obtained as a brownish, sticky, viscous materialhaving a nice fragrance. The color was likely caused by chlorophyll andother residual chromophoric compounds. For an exact yield determination,the tubes and separator were rinsed out with acetone and the acetone wasevaporated to give an addition 9 g of extract. The total extract amountwas 74 g. Based on the weight of the starting material, the yield of theextract was 1.88%. The content of oleandrin in the extract wascalculated using high pressure liquid chromatography and massspectrometry to be 560.1 mg, or a yield of 0.76%.

Method B. With Mixture of Carbon Dioxide and Ethanol

Powdered oleander leaves were prepared by harvesting, washing, anddrying oleander leaf material, then passing the oleander leaf materialthrough a comminuting and dehydrating apparatus such as those describedin U.S. Pat. Nos. 5,236,132, 5,598,979, 6,517,015, and 6,715,705. Theweight of the starting material used was 3.85 kg.

The starting material was combined with pure CO₂ and 5% ethanol as amodifier at a pressure of 280 bar (28 MPa, 4061 psi) and atemperature of50° C. (122° F.) in an extractor device. A total of 160 kg of CO₂ and 8kg ethanol was used, to give a solvent to raw material ratio of 43.6to 1. The mixture of CO₂, ethanol, and raw material was then passedthrough a separator device, which changed the pressure and temperatureof the mixture and separated the extract from the carbon dioxide.

The extract (207 g) was obtained after the removal of ethanol as a darkgreen, sticky, viscous mass obviously containing some chlorophyll. Basedon the weight of the starting material, the yield of the extract was5.38%. The content of oleandrin in the extract was calculated using highpressure liquid chromatography and mass spectrometry to be 1.89 g, or ayield of 0.91%.

Example 2 Hot-Water Extraction of Powdered Oleander Leaves ComparativeExample

Hot water extraction is typically used to extract oleandrin and otheractive components from oleander leaves. Examples of hot water extractionprocesses can be found in U.S. Pat. Nos. 5,135,745 and 5,869,060.

A hot water extraction was carried out using 5 g of powdered oleanderleaves. Ten volumes of boiling water (by weight of the oleander startingmaterial) were added to the powdered oleander leaves and the mixture wasstirred constantly for 6 hours. The mixture was then filtered and theleaf residue was collected and extracted again under the sameconditions. The filtrates were combined and lyophilized. The appearanceof the extract was brown. The dried extract material weighed about 1.44g. 34.21 mg of the extract material was dissolved in water and subjectedto oleandrin content analysis using high pressure liquid chromatographyand mass spectrometry. The amount of oleandrin was determined to be 3.68mg. The oleandrin yield, based on the amount of extract, was calculatedto be 0.26%.

Example 3 Preparation of Pharmaceutical Compositions Method A.Cremophor-Based Drug Delivery System

The following ingredients were provided in the amounts indicated.

Reagent Percent of Formulation Name Function (% w/w) Antiviralcomposition Active agent 3.7 Vitamin E Antioxidant 0.1 LabrasolSurfactant 9.2 Ethanol Co-solvent 9.6 Cremophor EL Surfactant 62.6Cremophor RH40 Surfactant 14.7

The excipients were dispensed into ajar and shook in aNew BrunswickScientific C24KC Refrigerated Incubator shaker for 24 hours at 60° C. toensure homogeneity. The samples were then pulled and visually inspectedfor solubilization. Both the excipients and antiviral composition weretotally dissolved for all formulations after 24 hours. Method B.GMO/Cremophor-based drug delivery system

The following ingredients were provided in the amounts indicated.

Reagent Percent of Formulation Name Function (% w/w) antiviralcomposition Active agent 4.7 Vitamin E Antioxidant 0.1 LabrasolSurfactant 8.5 Ethanol Co-solvent 7.6 Cremophor EL Surfactant 56.1Glycerol Monooleate Surfactant 23.2

The procedure of Method A was followed.

Method C. Labrasol-Based Drug Delivery System

The following ingredients were provided in the amounts indicated.

Reagent Percent of Name Function Formulation (% w/w) antiviralcomposition Active agent 3.7 Vitamin E Antioxidant 0.1 LabrasolSurfactant 86.6 Ethanol Co-solvent 9.6

The procedure of Method A was followed.

Method D. Vitamin E-TPGS Based Micelle Forming System

The following ingredients were provided in the amounts indicated.

Component Function Weight % (w/w) Vitamin E Antioxidant 1.0 Vitamin ETPGS Surfactant 95.2 antiviral composition Active agent 3.8

The procedure of Method A was followed.

Method E. Multi-Component Drug Delivery System

The following ingredients were provided in the amounts indicated.

Component Weight (g) Weight % (w/w) Vitamin E 10.0 1.0 Cremophor ELP580.4 55.9 Labrasol 89.0 8.6 Glycerol Monooleate 241.0 23.2 Ethanol 80.07.7 antiviral composition 38.5 3.7 Total 1038.9 100

The procedure of Method A was followed.

Method F. Multi-Component Drug Delivery System

The following ingredients were provided in the amounts indicated anincluded in a capsule.

Component Tradename Weight % (w/w) antiviral composition FLAVEXNaturextrakte 0.6 Vitamin E 1.3 Caprylocaproyl Labrasol 11.1polyoxyglycerides Gattefosse 3074TPD Lauroyl Gelucire 44/14 14.6polyoxyglycerides Gattefosse 3061TPD Polyoxyl 35 Castor Kolliphor 72.4oil BASF Corp. 50251534 Total 100

The procedure of Method A was followed.

Example 4 Preparation of Enteric Coated Capsules Step I: Preparation ofLiquid-Filled Capsule

Hard gelatin capsules (50 counts, 00 size) were filled with a liquidcomposition of Example 3. These capsules were manually filled with 800mg of the formulation and then sealed by hand with a 50% ethanol/50%water solution. The capsules were then banded by hand with 22% gelatinsolution containing the following ingredients in the amounts indicated.

Ingredient Wt. (g) Gelatin 140.0 Polysorbate 80 6.0 Water 454.0 Total650.0

The gelatin solution mixed thoroughly and allowed to swell for 1-2hours. After the swelling period, the solution was covered tightly andplaced in a 55° C. oven and allowed to liquefy. Once the entire gelatinsolution was liquid, the banding was performed

Using a pointed round 3/0 artist brush, the gelatin solution was paintedonto the capsules. Banding kit provided by Shionogi was used. After thebanding, the capsules were kept at ambient conditions for 12 hours toallow the band to cure.

Step II: Coating of Liquid-Filled Capsule

A coating dispersion was prepared from the ingredients listed in thetable below.

Ingredient Wt. % Solids % Solids (g) g/Batch Eudragit L30D55 40.4 60.576.5 254.9 TEC 1.8 9.0 11.4 11.4 AlTalc 500V 6.1 30.5 38.5 38.5 Water51.7 na na 326.2 Total 100.0 100.0 126.4 631.0

If banded capsules according to Step I were used, the dispersion wasapplied to the capsules to a 20.0 mg/cm² coating level. The followingconditions were used to coat the capsules.

Parameters Set-up Coating Equipment Vector LDCS-3 Batch Size 500 g InletAir Temp. 40° C. Exhaust Air Temp. 27-30° C. Inlet Air Volume 20-25 CFMPan Speed 20 rpm Pump Speed 9 rpm (3.5 to 4.0 g/min) Nozzle Pressure 15psi Nozzle diameter 1.0 mm Distance from tablet bed* 2-3 in *Spraynozzle was set such that both the nozzle and spray path were under theflow path of inlet air.

Example 5 Treatment of Zika Virus Infection in a Subject Method A.Antiviral Composition Therapy

A subject presenting with Zika virus infection is prescribed antiviralcomposition, and therapeutically relevant doses are administered to thesubject according to a prescribed dosing regimen for a period of time.The subject's level of therapeutic response is determined periodically.The level of therapeutic response can be determined by determining thesubject's Zika virus titre in blood or plasma. If the level oftherapeutic response is too low at one dose, then the dose is escalatedaccording to a predetermined dose escalation schedule until the desiredlevel of therapeutic response in the subject is achieved. Treatment ofthe subject with antiviral composition is continued as needed and thedose or dosing regimen can be adjusted as needed until the patientreaches the desired clinical endpoint.

Method B. Combination Therapy: Antiviral Composition with Another Agent

Method A, above, is followed except that the subject is prescribed andadministered one or more other therapeutic agents for the treatment ofZika virus infection or symptoms thereof. Then one or more othertherapeutic agents can be administered before, after or with theantiviral composition. Dose escalation (or de-escalation) of the one ormore other therapeutic agents can also be done.

Example 6 In Vitro Evaluation of Antiviral Activity Against Zika VirusInfection Method A. Pure Compound

Vero E6 cells (aso known as Vero C1008 cells, ATTC No. CRL-1586;https://www.atcc.org/Products/All/CRL-1586.aspx) were infected with ZIKV(Zika virus strain PRVABC59; ATCC VR-1843;https://www.atcc.org/Products/All/VR-1843.aspx) at an MOI (multiplicityof infection) of 0.2 in the presence of cardiac glycoside. Cells wereincubated with virus and compound for 1 hr, after which the inoculum andcompound were discarded. Cells were given fresh medium and incubated for48 hr, after which they were fixed with formalin and stained for ZIKVinfection. Representative infection rates for oleandrin (FIG. 1A) anddigoxin (FIG. 1B) as determined by scintigraphy are depicted. Othercompounds are evaluated under the same conditions and exhibit veryvarying levels of antiviral activity against Zika virus.

Method B. Compound in Extract Form

An extract containing a target compound being tested is evaluated asdetailed in Method A, except that the amount of extract is normalized tothe amount of target compound in the extract. For example, an extractcontaining 2% wt of oleandrin contains 20 microg of oleandrin per 1 mgof extract. Accordingly, if the intended amount of oleandrin forevaluation is 20 microg, then 1 mg of extract would be used in theassay.

Example 7 Preparation of a tablet comprising antiviral composition

An initial tabletting mixture of 3% Syloid 244FP and 97%microcrystalline cellulose (MCC) was mixed. Then, an existing batch ofcomposition prepared according to Example 3 was incorporated into theSyloid/MCC mixture via wet granulation. This mixture is labeled “InitialTabletting Mixture) in the table below. Additional MCC was addedextra-granularly to increase compressibility. This addition to theInitial Tabletting Mixture was labeled as “Extra-granular Addition.” Theresultant mixture from the extra-granular addition was the samecomposition as the “Final Tabletting Mixture.”

Component Weight (g) Weight % (w/w) Initial Tabletting MixtureMicrocrystalline cellulose 48.5 74.2 Colloidal Silicon Dioxide/Syloid1.5 2.3 244FP Formulation from Ex. 3 15.351 23.5 Total 65.351 100.0

Extragranular addition Component Weight (g) Weight % (w/w) InitialTabulating Mixture 2.5 50.0 Microcrystalline cellulose 2.5 50.0 Total 5100.0

Abbreviated Component Weight (g) Weight % (w/w) Microcrystallinecellulose 4.36 87.11 Colloidal Silicon Dioxide/Syloid 0.06 1.15 244FPFormulation from Ex. 3 0.59 11.75 Total 5.00 100

Final Tabletting Mixture:

Detailed Component Weight (g) Weight % (w/w) Microcrystalline cellulose4.36 87.11 Colloidal Silicon Dioxide/Syloid 0.06 1.15 244FP Vitamin E0.01 0.11 Cremophor ELP 0.33 6.56 Labrasol 0.05 1.01 Glycerol Monooleate0.14 2.72 Ethanol 0.05 0.90 SCF extract 0.02 0.44 Total 5.00 100.00

Syloid 244FP is a colloidal silicon dioxide manufactured by GraceDavison. Colloidal silicon dioxide is commonly used to provide severalfunctions, such as an adsorbant, glidant, and tablet disintegrant.Syloid 244FP was chosen for its ability to adsorb 3 times its weight inoil and for its 5.5 micron particle size.

Example 8 HPLC Analysis of Solutions Containing Oleandrin

Samples (oleandrin standard, SCF extract and hot-water extract) wereanalyzed on HPLC (Waters) using the following conditions: Symmetry C18column (5.0 μm, 150×4.6 mm I.D.; Waters); Mobile phase ofMeOH:water=54:46 (v/v) and flow rate at 1.0 ml/min. Detection wavelengthwas set at 217 nm. The samples were prepared by dissolving the compoundor extract in a fixed amount of HPLC solvent to achieve an approximatetarget concentration of oleandrin. The retention time of oleandrin canbe determined by using an internal standard. The concentration ofoleandrin can be determined/calibrated by developing a signal responsecurve using the internal standard.

Example 9 Preparation of Pharmaceutical Composition

A pharmaceutical composition of the invention can be prepared any of thefollowing methods. Mixing can be done under wet or dry conditions. Thepharmaceutical composition can be compacted, dried or both duringpreparation. The pharmaceutical composition can be portioned into dosageforms.

Method A

At least one pharmaceutical excipient is mixed with at least oneantiviral compound disclosed herein.

Method B

At least one pharmaceutical excipient is mixed with at least twoantiviral compounds disclosed herein.

Method C

At least one pharmaceutical excipient is mixed with at least one cardiacglycosides disclosed herein.

Method D.

At least one pharmaceutical excipient is mixed with at least twotriterpenes disclosed herein.

Method E

At least one pharmaceutical excipient is mixed with at least one cardiacglycoside disclosed herein and at least two triterpenes disclosedherein.

Method D.

At least one pharmaceutical excipient is mixed with at least threetriterpenes disclosed herein.

Example 10 Preparation of Triterpene Mixtures

The following compositions were made by mixing the specified triterpenesin the approximate molar ratios indicated.

Triterpene (Approximate Relative Molar Content) Composition Oleanolicacid (O) Ursolic acid (U) Betulinic acid (B) I (A-C) 3 2.2 1 II (A-C)7.8 7.4 1 III (A-C) 10 1 1 IV (A-C) 1 10 1 V (A-C) 1 1 10 VI (A-C) 1 1 0VII (A-C) 1 1 1 VIII (A-C) 10 1 0 IX (A-C) 1 10 0

For each composition, three different respective solutions were made,whereby the total concentration of triterpenes in each solution wasapproximately 9 μM, 18 μM, or 36 μM.

Composition Triterpene (Approximate Content of Each, μM) (totaltriterpene Oleanolic Ursolic Betulinic content, μM) acid (O) acid (U)acid (B) I-A(36) 17.4 12.8 5.8 I-B (18) 8.7 6.4 2.9 I-C (9) 4.4 3.2 1.5II-A (36) 17.3 16.4 2.2 II-B (18) 8.7 8.2 1.1 II-C (9) 4.3 4.1 0.6 III-A(36) 30 3 3 III-B (18) 15 1.5 1.5 III-C (9) 7.5 0.75 0.75 IV-A (36) 3 303 IV-B (18) 1.5 15 1.5 IV-C (9) 0.75 7.5 0.75 V-A (36) 3 3 30 V-B (18)1.5 1.5 15 V-C (9) 0.75 0.75 7.5 VI-A (36) 18 18 0 VI-B (18) 9 9 0 VI-C(9) 4.5 4.5 0 VII-A (36) 12 12 12 VII-B (18) 6 6 6 VII-C (9) 3 3 3VIII-A (36) 32.7 3.3 0 VIII-B (18) 16.35 1.65 0 VIII-C (9) 8.2 0.8 0IX-A (36) 3.3 32.7 0 IX-B (18) 1.65 16.35 0 IX-C (9) 0.8 8.2 0

Example 11 Preparation of Antiviral Compositions

Antiviral compositions can be prepared by mixing the individualtriterpene components thereof to form a mixture. The triterpene mixturesprepared above that provided acceptable antiviral activity wereformulated into antiviral compositions. Antiviral composition witholeanolic acid and ursolic acid

Known amounts of oleanolic acid and ursolic acid were mixed according toa predetermined molar ratio of the components as defined herein. Thecomponents were mixed in solid form or were mixed in solvent(s), e.g.methanol, ethanol, chloroform, acetone, propanol, dimethyl sulfoxide(DMSO), dimethylformamide (DMF), dimethylacetamide (DMAC),N-methylpyrrolidone (NMP), water or mixtures thereof. The resultantmixture contained the components in the relative molar ratios asdescribed herein.

For a pharmaceutically acceptable antiviral composition, at least onepharmaceutically acceptable excipient was mixed in with thepharmacologically active agents. An antiviral composition is formulatedfor administration to a mammal. Antiviral composition with oleanolicacid and betulinic acid

Known amounts of oleanolic acid and betulinic acid were mixed accordingto a predetermined molar ratio of the components as defined herein. Thecomponents were mixed in solid form or were mixed in solvent(s), e.g.methanol, ethanol, chloroform, acetone, propanol, dimethyl sulfoxide(DMSO), dimethylformamide (DMF), dimethylacetamide (DMAC),N-methylpyrrolidone (NMP), water or mixtures thereof. The resultantmixture contained the components in the relative molar ratios asdescribed herein.

For a pharmaceutically acceptable antiviral composition, at least onepharmaceutically acceptable excipient was mixed in with thepharmacologically active agents. An antiviral composition is formulatedfor administration to a mammal. Antiviral composition with oleanolicacid, ursolic acid, and betulinic acid

Known amounts of oleanolic acid, ursolic acid and betulinic acid weremixed according to a predetermined molar ratio of the components asdefined herein. The components were mixed in solid form or were mixed insolvent(s), e.g. methanol, ethanol, chloroform, acetone, propanol,dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide(DMAC), N-methylpyrrolidone (NMP), water or mixtures thereof. Theresultant mixture contained the components in the relative molar ratiosas described herein.

For a pharmaceutically acceptable antiviral composition, at least onepharmaceutically acceptable excipient was mixed in with thepharmacologically active agents. An antiviral composition is formulatedfor administration to a mammal. Antiviral composition with oleadrin,oleanolic acid, ursolic acid, and betulinic acid

Known amounts of oleandrin oleanolic acid, ursolic acid and betulinicacid were mixed according to a predetermined molar ratio of thecomponents as defined herein. The components were mixed in solid form orwere mixed in solvent(s), e.g. methanol, ethanol, chloroform, acetone,propanol, dimethyl sulfoxide (DMSO), dimethylformamide (DMF),dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), water or mixturesthereof. The resultant mixture contained the components in the relativemolar ratios as described herein.

For a pharmaceutically acceptable antiviral composition, at least onepharmaceutically acceptable excipient was mixed in with thepharmacologically active agents. An antiviral composition is formulatedfor administration to a mammal.

Example 12 Treatment of Filovirus Infection in a Subject

Exemplary Filovirus infections include Ebolavirus and Marburgvirus.

Method A. Antiviral Composition therapy

A subject presenting with Filovirus infection is prescribed antiviralcomposition, and therapeutically relevant doses are administered to thesubject according to a prescribed dosing regimen for a period of time.The subject's level of therapeutic response is determined periodically.The level of therapeutic response can be determined by determining thesubject's Filovirus titre in blood or plasma. If the level oftherapeutic response is too low at one dose, then the dose is escalatedaccording to a predetermined dose escalation schedule until the desiredlevel of therapeutic response in the subject is achieved. Treatment ofthe subject with antiviral composition is continued as needed and thedose or dosing regimen can be adjusted as needed until the patientreaches the desired clinical endpoint.

Method B. Combination therapy: antiviral composition with another agent

Method A, above, is followed except that the subject is prescribed andadministered one or more other therapeutic agents for the treatment ofFilovirus infection or symptoms thereof. Then one or more othertherapeutic agents can be administered before, after or with theantiviral composition. Dose escalation (or de-escalation) of the one ormore other therapeutic agents can also be done.

Example 13 Treatment of Flavivirus Infection in a Subject

Exemplary Flavivirus infections include Yellow Fever, Dengue Fever,Japanese Enchephalitis, West Nile Viruses, Zikavirus, Tick-borneEncephalitis, Kyasanur Forest Disease, Alkhurma Disease, Chikungunyavirus, Omsk Hemorrhagic Fever, Powassan virus infection.

Method A. Antiviral Composition Therapy

A subject presenting with Flavivirus infection is prescribed antiviralcomposition, and therapeutically relevant doses are administered to thesubject according to a prescribed dosing regimen for a period of time.The subject's level of therapeutic response is determined periodically.The level of therapeutic response can be determined by determining thesubject's Flavivirus titre in blood or plasma. If the level oftherapeutic response is too low at one dose, then the dose is escalatedaccording to a predetermined dose escalation schedule until the desiredlevel of therapeutic response in the subject is achieved. Treatment ofthe subject with antiviral composition is continued as needed and thedose or dosing regimen can be adjusted as needed until the patientreaches the desired clinical endpoint.

Method B. Combination Therapy: Antiviral Composition with Another Agent

Method A, above, is followed except that the subject is prescribed andadministered one or more other therapeutic agents for the treatment ofFlavivirus infection or symptoms thereof. Then one or more othertherapeutic agents can be administered before, after or with theantiviral composition. Dose escalation (or de-escalation) of the one ormore other therapeutic agents can also be done.

Example 14 Evaluation of Antiviral Activity Against Zikavirus and DengueVirus

A CPE-based antiviral assay was performed by infecting target cells inthe presence or absence of test compositions, at a range ofconcentrations. Infection of target cells by results in cytopathiceffects and cell death. In this type of assay, reduction of CPE in thepresence of test composition, and the corresponding increase in cellviability, is used as an indicator of antiviral activity. For CPE-basedassays, cell viability was determined with a neutral red readout. Viablecells incorporate neutral red in their lysosomes. Uptake of neutral redrelies on the ability of live cells to maintain a lower pH inside theirlysosomes than in the cytoplasm, and this active process requires ATP.Once inside the lysosome, the neutral red dye becomes charged and isretained intracellularly. After a 3-hour incubation with neutral red(0.033%), the extracellular dye was removed, cells were washed with PBS,and the intracellular neutral red was solubilized with a solution of 50%ethanol+1% acetic acid. The amount of neutral red in solution wasquantified by reading the absorbance (optical density) of each well at490 nm

Adherent cell lines were used to evaluate the antiviral activity ofcompositions against a panel of viruses. Compositions were pre-incubatedwith the target cells for 30 min before the addition of virus to thecells. The compositions were present in the cell culture medium for theduration of the infection incubation period. For each infection assay, aviability assay was set up in parallel using the same concentrations ofcompositions (duplicates) to determine cytotoxicity effects of thecompositions in the absence of virus.

The antiviral activity of test compositions was determined by comparinginfection levels (for immunostaining-based assay) or viability (forCPE-based assays) of cells under test conditions to the infection levelor viability of uninfected cells. Cytotoxic effects were evaluated inuninfected cells by comparing viability in the presence of inhibitors tothe viability of mock-treated cells. Cytotoxicity was determined by anXTT viability assay, which was conducted at the same timepoint as thereadout for the corresponding infection assay.

Test compositions were dissolved in 100% methanol. Eight concentrationsof the compositions were generated (in duplicate) by performing 8-folddilutions, starting with 50 μM as the highest concentration tested. Thehighest test concentration of composition (50 μM) resulted in a 0.25%final concentration of methanol (v/v %) in the culture medium. An 8-folddilution series of methanol vehicle was included in each assay plate,with concentrations mirroring the final concentration of methanol ineach composition test condition. When possible, the EC50 and CC50 of thecomposition was determined for each assay using GraphPadPrism software.

Antiviral activity was evaluated by the degree of protection againstvirus-induced cytopathic effects (CPE). Cells were challenged with virusin the presence of different concentrations of control or compositions.The extent of protection against CPE was monitored after 6 days (ZIKV,Zikavirus) or 7 days (DENV, Dengue virus) post infection by quantifyingcell viability in different test conditions and comparing values withthat of untreated cells and cells treated with vehicle alone (infectionmedium).

Quality controls for the neutralization assay were performed on everyplate to determine: i) signal to background (S/B) values; ii) inhibitionby the known inhibitors, and iii) variation of the assay, as measured bythe coefficient of variation (C.V.) of all data points. Overallvariation in the infection assays ranged from 3.4% to 9.5%, and overallvariation in the viability assays ranged from 1.4% to 3.2%, calculatedas the average of all C.V. values. The signal-to-background (S/B) forthe infection assays ranged from 2.9 to 11.0, while thesignal-to-background (S/B) for the viability assays ranged from 6.5 to29.9.

Protection of DENV2-induced cytopathic effect (CPE) with Neutral Redreadout: For the DENV2 antiviral assay, the 08-10381 Montserrat strainwas used. Viral stocks were generated in C6/36 insect cells. Vero cells(epithelial kidney cells derived from Cercopithecus aethiops) weremaintained in MEM with 5% FBS (MEM5). For both the infection and theviability assays, cells were seeded at 10,000 cells per well in 96-wellclear flat bottom plates and maintained in MEM5 at 37° C. for 24 hours.The day of infection, samples were diluted 8-fold in U-bottom platesusing MEM with 1% bovine serum albumin (BSA). Test material dilutionswere prepared at 1.25× the final concentration and 40 μl were incubatedwith the target cells at 37° C. for 30 minutes. Following the testmaterial pre-incubation, 10 μl of virus dilutions prepared in MEM with1% BSA was added to each well (50 μl final volume per well) and plateswere incubated at 37° C. in a humidified incubator with 5% CO₂ for 3hours. The volume of virus used in the assay was previously determinedto produce a signal in the linear range inhibited by Ribavirin andcompound A3, known inhibitors of DENV2. After the infection incubation,cells were washed with PBS, then MEM containing 2% FBS (MEM2) to removeunbound virus. Subsequently, 50 μl of medium containing inhibitordilutions prepared at a 1× concentration in MEM2 was added to each well.The plate was incubated at 37° C. in the incubator (5% CO₂) for 7 days.Controls with no virus (“mock-infected”), infected cells incubated withmedium alone, infected cells incubated with vehicle alone (methanol),and wells without cells (to determine background) were included in theassay plate. Control wells containing 50 μM Ribavirin and 0.5 μMcompound A3 were also included on the assay plate. After 7 days ofinfection, cells were stained with neutral red to monitor cellviability. Test materials were evaluated in duplicates using serial8-fold dilutions in infection medium. Controls included cells incubatedwith no virus (“mock-infected”), infected cells incubated with mediumalone, or infected cells in the presence of Ribavirin (0.5 μM) or A3(0.5 μM). A full duplicate inhibition curve with methanol vehicle onlywas included on the same assay plate.

Protection of ZIKV-induced cytopathic effect (CPE) with Neutral Redreadout: For the ZIKV antiviral assay, the PLCal_ZV strain was used.Vero cells (epithelial kidney cells derived from Cercopithecus aethiops)were maintained in MEM with 5% FBS (MEM5). For both the infection andthe viability assays, cells were seeded at 10,000 cells per well in96-well clear flat bottom plates and maintained in MEM5 at 37° C. for 24hours. The day of infection, samples were diluted 8-fold in U-bottomplates using MEM with 1% bovine serum albumin (BSA). Test materialdilutions were prepared at 1.25× the final concentration and 40μl wereincubated with the target cells at 37° C. for 30 minutes. Following thetest material pre-incubation, 10 μl of virus dilutions prepared in MEMwith 1% BSA was added to each well (50p final volume per well) andplates were incubated at 37° C. in a humidified incubator with 5% CO₂for 3 hours. After the infection incubation, cells were washed with PBS,then MEM containing 2% FBS (MEM2) to remove unbound virus. Subsequently,50l of medium containing inhibitor dilutions prepared at a 1×concentration in MEM2 was added to each well. The plate was incubated at37° C. in the incubator (5% CO₂) for 6 days. Controls with no virus(“mock-infected”), infected cells incubated with medium alone, infectedcells incubated with vehicle alone (methanol), and wells without cells(to determine background) were included in the assay plate. After 6 daysof infection, cells were stained with neutral red to monitor cellviability. Test materials were evaluated in duplicates using serial8-fold dilutions in infection medium. Controls included cells incubatedwith no virus (“mock-infected”), infected cells incubated with mediumalone, or infected cells in the presence of A3 (0.5 μM). A fullduplicate inhibition curve with methanol vehicle only was included onthe same assay plate.

Analysis of CPE-based viability data: for the neutral red assays, cellviability was determined by monitoring the absorbance at 490 nm. Theaverage signal obtained in wells with no cells was subtracted from allsamples. Then, all data points were calculated as a percentage of theaverage signal observed in the 8 wells of mock (uninfected) cells on thesame assay plate. Infected cells treated with medium alone reduced thesignal to an average of 4.2% (for HRV), 26.9% (for DENV), and 5.1% (forZIKV) of that observed in uninfected cells. The signal-to-background(S/B) for this assay was 2.9 (for DENV), and 7.2 (for ZIKV), determinedas the viability percentage in “mock-infected” cells compared to that ofinfected cells treated with vehicle only.

Viability assay (XTT) to assess compound-induced cytotoxicity:Mock-infected cells were incubated with inhibitor dilutions (or mediumonly) using the same experimental setup and inhibitor concentrations aswas used in the corresponding infection assay. The incubationtemperature and duration of the incubation period mirrored theconditions of the corresponding infection assay. Cell viability wasevaluated with an XTT method. The XTT assay measures mitochondrialactivity and is based on the cleavage of yellow tetrazolium salt (XTT),which forms an orange formazan dye. The reaction only occurs in viablecells with active mitochondria. The formazan dye is directly quantifiedusing a scanning multi-well spectrophotometer. Background levelsobtained from wells with no cells were subtracted from all data-points.Controls with methanol vehicle alone (at 7 concentrations mirroring thefinal percent methanol of each Oleandrin test wells) were included inthe viability assay plate. The extent of viability was monitored bymeasuring absorbance at 490 nm.

Analysis of cytotoxicity data: For the XTT assays, cell viability wasdetermined by monitoring the absorbance at 490 nm. The average signalobtained in wells with no cells was subtracted from all samples. Then,all data points were calculated as a percentage of the average signalobserved in the 8 wells of mock (uninfected) cells on the same assayplate. The signal-to-background (S/B) for this assay was 29.9 (for IVA),8.7 (for HRV), 6.5 (for DENV), and 6.7 (for ZIKV), determined as theviability percentage in “mock-infected” cells compared to the signalobserved for wells without cells.

Example 15 Evaluation of Antiviral Activity Against Filovirus(Ebolavirus and Marburgvirus) Method A.

Vero E6 cells were infected with EBOV/Kik (A, MOI=1) or MARV/Ci67 (B,MOI=1) in the presence of oleandrin, digoxin or PBI-05204, anoleandrin-containing plant extract. After 1 hr, inoculum and compoundswere removed and fresh medium added to cells. 48 hr later, cells werefixed and immunostained to detect cells infected with EBOV or MARV.Infected cells were enumerated using an Operetta. C) Vero E6 weretreated with compound as above. ATP levels were measured byCellTiter-Glo as a measurement of cell viability.

Method B.

Vero E6 cells were infected with EBOV (A,B) or MARV (C,D). At 2 hrpost-infection (A,C) or 24 hr post-infection (B,D), oleandrin orPBI-05204 was added to cells for 1 hr, then discarded and cells werereturned to culture medium. At 48 hr post-infection, infected cells wereanalyzed as in FIG. 1.

Method C.

Vero E6 cells were infected with EBOV or MARV in the presence ofoleandrin or PBI-05204 and incubated for 48 hr. Supernatants frominfected cell cultures were passaged onto fresh Vero E6 cells, incubatedfor 1 hr, then discarded (as depicted in A). Cells containing passagedsupernatant were incubated for 48 hr. Cells infected with EBOV (B) orMARV (C) were detected as described previously. Control infection rateswere 66% for EBOV and 67% for MARV.

Example 16 Evaluation of Antiviral Activity Against Togaviridae VirusAlphavirus: VEEV and WEEV

Vero E6 cells were infected with Venezuelan equine encephalitis virus(A, MOI=0.01) or Western equine encephalitis virus (B, MOI=0.1) for 18hr in the presence or absence of indicated compounds. Infected cellswere detected as described herein and enumerated on an Operetta.

Example 17 Treatment of Paramyxoviridae Infection in a Subject

Exemplary Paramyxoviridae family viral infections include Henipavirusgenus infection, Nipah virus infection, or Hendra virus infection.

Method A. Antiviral Composition Therapy

A subject presenting with Paramyxoviridae family infection is prescribedantiviral composition, and therapeutically relevant doses areadministered to the subject according to a prescribed dosing regimen fora period of time. The subject's level of therapeutic response isdetermined periodically. The level of therapeutic response can bedetermined by determining the subject's virus titre in blood or plasma.If the level of therapeutic response is too low at one dose, then thedose is escalated according to a predetermined dose escalation scheduleuntil the desired level of therapeutic response in the subject isachieved. Treatment of the subject with antiviral composition iscontinued as needed and the dose or dosing regimen can be adjusted asneeded until the patient reaches the desired clinical endpoint.

Method B. Combination Therapy: Antiviral Composition with Another Agent

Method A, above, is followed except that the subject is prescribed andadministered one or more other therapeutic agents for the treatment ofParamyxoviridae family infection or symptoms thereof. Then one or moreother therapeutic agents can be administered before, after or with theantiviral composition. Dose escalation (or de-escalation) of the one ormore other therapeutic agents can also be done.

Example 18 Cell-Lines and Isolation of Primary huPBMC's

The virus-producing HTLV-1-transformed (HTLV-1+) SLB1 lymphomaT-cell-line (Arnold et al., 2008; kindly provided by P. Green, The OhioState University-Comprehensive Cancer Center) was cultured in ahumidified incubator at 37° C. under 10% CO₂ in Iscove's ModifiedDulbecco's Medium (IMDM; ATCC No. 30-2005), supplemented with 10%heat-inactivated fetal bovine serum (FBS; Biowest), 100 U/ml penicillin,100 μg/ml streptomycin-sulfate, and 20 μg/ml gentamycin-sulfate (LifeTechnologies).

Primary human peripheral blood mononuclear cells (huPBMCs) were isolatedfrom whole blood samples, provided without identifiers by the SMUMemorial Health Center under a protocol approved by the SMUInstitutional Review Board and consistent with Declaration of Helsinkiprinciples. In brief, 2 ml of whole blood was mixed with an equal volumeof sterile phosphate-buffered saline (PBS), pH 7.4, in polypropyleneconical tubes (Corning) and then the samples were gently layered over 3ml of Lymphocyte Separation Medium (MP Biomedicals). The samples werecentrifuged for 30 min at 400×g in a swinging bucket rotor at room temp.The buffy-coat huPBMCs were subsequently aspirated, washed 2× inRPMI-1640 medium (ATCC No. 30-2001), and pelleted by centrifugation for7 min at 260×g. The cells were resuspended in RPMI-1640 medium,supplemented with 20% FBS, 100 U/ml penicillin, 100 μg/mlstreptomycin-sulfate, 20 μg/ml gentamycin-sulfate, and 50 U/mlrecombinant human interleukin-2 (hu-IL-2; Roche Applied Science), andstimulated for 24 hrs with 10 ng/ml phytohemagglutinin (PHA;Sigma-Aldrich) and grown at 37° C. under 10% CO₂ in a humidifiedincubator. On the following day, the cells were pelleted bycentrifugation for 7 min at 260×g and washed 2× with RPMI-1640 medium toremove the PHA, and then resuspended and cultured in complete medium,supplemented with antibiotics and 50 U/ml hu-IL-2.

Example 19 Generation of GFP-Expressing HTLV-1+ SLB1/pLenti-GFP T-CellClones

To generate the GFP-expressing HTLV-1+ SLB1 T-cell clones, 2×10⁶ SLB1cells were plated in 60 mm² tissue-culture dishes (Corning) in IMDM,supplemented with 10% heat-inactivated FBS and antibiotics, and thentransduced with lentiviral particles containing apLenti-6.2/V5-DEST-green fluorescent protein expression vector whichalso carries a blasticidin-resistance gene. After 6 hrs, the transducedcells were pelleted by centrifugation for 7 min at 260×g at roomtemperature, washed 2× with serum-free IMDM, and resuspended in completemedium supplemented with 5 μg/ml blasticidin (Life Technologies) andaliquoted into 96-well microtiter plates (Corning). The cultures weremaintained with blasticidin-selection for two weeks in a humidifiedincubator at 37° C. and 10% CO₂. The GFP-expressing lymphoblasts werescreened by fluorescence-microscopy, and then plated bylimiting-dilution in 96-well microtiter plates to obtain homogenousGFP-expressing cell clones. The resulting HTLV-1+ SLB1/pLenti-GFPT-lymphocyte clones were expanded and repeatedly passaged; and theexpression of GFP was confirmed by sodium dodecyl sulfate-polyacrylamidegel electrophoresis (SDS-PAGE) and immunoblotting using a rabbitpolyclonal Anti-GFP (FL) antibody (Santa Cruz Biotechnology).

Example 20 Quantitation of Virus Production and Particle Infectivity byAnti-HTLV-1 p19^(Gag) ELISA's

To determine the effects of oleandrin or an extract of N. oleander uponHTLV-1 proviral replication and the release of newly-synthesizedextracellular virus particles, the HTLV-1+ SLB1 lymphoma T-cell-line wasplated at 2×10⁴ cells per well in 300 μl of complete medium,supplemented with antibiotics, in 96-well microtiter plates andincubated at 37° C. under 10% C02. The purified oleandrin compound andextract of N. oleander (Phoenix Biotechnology; see Singh et al., 2013)were resuspended in the Vehicle solution (20% v/v dimethyl sulfoxide,DMSO, in MilliQ distilled/deionized H₂O) at a stock concentration of 2mg/ml and then sterilized using a luer-lock 0.2 μm syringe filter(Millipore). The HTLV-1+ SLB1 cells were treated with oleandrin or theN. oleander extract at concentrations of 10, 50, and 100 μg/ml, or withincreasing amounts (1.5, 7.5, and 15 μl) of the Vehicle control for 72hrs. The 96-well microtiter plates were then centrifuged for 7 min at260×g at room temp using an Eppendorf A-2-DWP swinging plate rotor topellet the cells, and the levels of extracellular p19^(Gag)-containingHTLV-1 particles released into the culture supernatants were quantifiedrelative to a p19^(Gag) protein standard by performing colorimetricAnti-p19^(Gag) enzyme-linked immunosorbent assays (ELISAs; Zeptometrix).The samples were analyzed with triplicate replicates on a BertholdTristar LB 941 multimode microplate-reader at 450 nm in absorbance mode.

To assess the infectivity of newly-synthesized extracellular HTLV-1particles collected from oleandrin-treated cells, 2×10⁴ HTLV-1+ SLB1T-lymphoblasts were plated in 300 μl of complete medium, supplementedwith antibiotics, and the cultures were treated for 72 hrs withincreasing concentrations (10, 50, and 100 μg/ml) of oleandrin or a N.oleander extract, or the Vehicle control (1.5, 7.5, and 15 μl). Then, 50μl of the virus-containing supernatants were used to directly infecthuPBMCs plated at a density of 2×10⁴ cells per well on 96-wellmicrotiter plates in complete medium, supplemented with antibiotics andhu-IL-2. The oleandrin compound, N. oleander extract, or Vehicle controlwere maintained in the huPBMCs culture medium to control for possiblere-infection events by newly-produced particles. After 72 hrs, therelative levels of extracellular p19^(Gag) containing HTLV-1 virionsreleased into the culture supernatants by the infected huPBMCs werequantified through Anti-HTLV-1 p19^(Gag) ELISAs.

Example 21 Measuring Cellular Apoptosis

To assess the relative cytotoxicity of the oleandrin compound, extractof N. oleander, or the Vehicle control in treated cell cultures, 2×10⁴HTLV-1+ SLB1 lymphoma T-cells or activated/cultured huPBMCs were platedin 300 μl of complete medium, supplemented with antibiotics, andmaintained at 37° C. under 10% C02 in a humidified incubator. Thecultures were treated with either increasing concentrations (10, 50, and100 μg/ml) of oleandrin or N. oleander extract, or the Vehicle control(1.5, 7.5, 15 ml) and incubated for 72 hrs. Cyclophosphamide (50 μM;Sigma-Aldrich)-treated cells were included as a positive control forapoptosis. The cells were then aspirated and plated on Permanox8-chamber tissue-culture slides (Nalge) that had been pre-treated with asterile 0.01% solution of Poly-L-Lysine and Concanavalin A (1 mg/ml;Sigma-Aldrich). The samples were subsequently stained using a microscopyapoptosis detection kit with Annexin V conjugated to fluoresceinisothiocyanate (Annexin V-FITC) and propidium iodide (PI;BD-Pharmingen), and the relative percentages of apoptotic (i.e., AnnexinV-FITC and/or PI-positive) cells per field were quantified in-triplicateby confocal fluorescence-microscopy using a 20× objective lens. Thetotal numbers of cells per field were quantified by microscopy using aDIC phase-contrast filter.

Example 22 HTLV-1 Transmission and Virological Synapse Formation inCo-Culture Assays

As the transmission of HTLV-1 typically occurs through direct contactbetween an infected cell and uninfected target cell across a virologicalsynapse (Igakura et al., 2003; Pais-Correia et al., 2010; Gross et al.,2016; Omsland et al., 2018; Majorovits et al., 2008), we tested whetheroleandrin, a N. oleander extract, or the Vehicle control might influencethe formation of virological synapses and/or the transmission ofinfectious HTLV-1 particles via intercellular interactions in vitro. Forthese experiments, 2×10⁴ virus-producing HTLV-1+ SLB1 T-cells wereplated in 96-well microtiter plates and treated with mitomycin C (100μg/ml) in 300 μl of complete medium for 2 hrs at 37° C. under 10% C02(Bryja et al., 2006). The culture media was then removed, the cells werewashed 2× with serum-free IMDM, and the cells were treated for either 15min or 3 hrs with increasing amounts (10, 50, and 100 μg/ml) ofoleandrin or N. oleander extract, or the Vehicle control (1.5, 7.5, and15 μl). Alternatively, 2×10⁴ of the GFP-expressing HTLV-1+SLB1/pLenti-GFP T-cells were plated on 8-chamber tissue-culture slidesin 300 μl of complete medium and treated with mitomycin C, washed 2×with serum-free IMDM, and then treated with oleandrin, N. oleanderextract, or the Vehicle control as described for confocal microscopyexperiments. We next aspirated the medium, washed the HTLV-1+ SLB1 cells2× with serum-free medium, and added 2×10⁴ huPBMCs to each well in 300μl of RPMI-1640 medium, supplemented with 20% FBS, antibiotics and 50U/ml hu-IL-2, and then co-cultured the cells for another 72 hrs (thecells were co-cultured for 6 hrs to visualize virological synapseformation and viral transmission by confocal microscopy using theSLB1/pLenti-GFP lymphoblasts) at 37° C. under 10% C02 in a humidifiedincubator. As a negative control, huPBMCs were cultured alone in theabsence of virus-producing cells. The oleandrin, N. oleander extract,and Vehicle were maintained in the co-culture medium. The relativelevels of extracellular p19^(Gag)-containing HTLV-1 particles releasedinto the co-culture supernatants as a result of intercellular viraltransmission were quantified by performing Anti-HTLV-1 p19^(Gag) ELISAs.Virological synapses formed between the GFP-positive HTLV-1+SLB/pLenti-GFP cells and huPBMCs were visualized usingimmunofluorescence-confocal microscopy by staining the fixed sampleswith an Anti-HTLV-1 gp21^(Env) primary antibody and a rhodaminered-conjugated secondary antibody. Diamidino-2-phenyl-indole,dihydrochloride (DAPI; Molecular Probes) nuclear-staining was includedfor comparison and to visualize uninfected (i.e., HTLV-1-negative)cells. The intercellular transmission of HTLV-1 to the huPBMCs inco-culture assays was quantified by counting the relative percentages ofHTLV-1 gp21^(Env)-positive (and GFP-negative) huPBMCs in 20 visualfields using a 20× objective lens.

Example 23 Microscopy

The Annexin V-FITC/PI-stained samples to quantify cellular apoptosis andcytotoxicity were visualized by confocal fluorescence-microscopy on aZeiss LSM800 instrument equipped with an Airyscan detector and stage CO₂incubator, using a Plan-Apochromat 20×/0.8 objective lens and Zeiss ZENsystem software (Carl Zeiss Microscopy). The formation of virologicalsynapses and viral transmission (i.e., determined by quantifying therelative percentages of Anti-HTLV-1 gp21^(Env)-positive huPBMCs) betweenthe mitomycin C-treated HTLV-1+ SLB1/pLenti-GFP lymphoblasts andcultured huPBMCs were visualized by immunofluorescence-confocalmicroscopy using a Plan-Apochromat 20×/0.8 objective lens. The relativefluorescence-intensities of the DAPI, Anti-HTLV-1 gp21^(Env)-specific(rhodamine red-positive), and GFP signals were graphically quantifiedusing the Zen 2.5D analysis tool (Carl Zeiss Microscopy). TheGFP-expressing HTLV-1+ SLB1/pLenti-GFP T-cell clones were screened byconfocal fluorescence-microscopy on a Nikon Eclipse TE2000-U invertedmicroscope and D-Eclipse confocal imaging system, equipped with 633 nmand 543 nm He/Ne and 488 nm Ar lasers, using a Plan Fluor 10×/0.30objective lens and DIC phase-contrast filter (Nikon Instruments).

Example 24 Statistical Analysis

The statistical significance of experimental data sets was determinedusing unpaired two-tailed Student's t-tests (alpha=0.05) and calculatedP-values using the Shapiro-Wilk normality test and Graphpad Prism 7.03software. The P-values were defined as: 0.1234 (ns), 0.0332 (*), 0.0021(**), 0.0002 (***), <0.0001 (****). Unless otherwise noted, error barsrepresent the SEM from at least three independent experiments.

Example 25 Treatment of Deltaretrovirus Infection in a Subject

Exemplary Deltaretrovirus infections include HTLV-1.

Method A. Antiviral Composition Therapy

A subject presenting with HTLV-1 infection is prescribed antiviralcomposition, and therapeutically relevant doses are administered to thesubject according to a prescribed dosing regimen for a period of time.The subject's level of therapeutic response is determined periodically.The level of therapeutic response can be determined by determining thesubject's HTLV-1 virus titre in blood or plasma. If the level oftherapeutic response is too low at one dose, then the dose is escalatedaccording to a predetermined dose escalation schedule until the desiredlevel of therapeutic response in the subject is achieved. Treatment ofthe subject with antiviral composition is continued as needed and thedose or dosing regimen can be adjusted as needed until the patientreaches the desired clinical endpoint.

Method B. Combination Therapy: Antiviral Composition with Another Agent

Method A, above, is followed except that the subject is prescribed andadministered one or more other therapeutic agents for the treatment ofHTLV-1 infection or symptoms thereof. Then one or more other therapeuticagents can be administered before, after or with the antiviralcomposition. Dose escalation (or de-escalation) of the one or more othertherapeutic agents can also be done. Exemplary other therapeutic agentsare described herein.

As used herein, the term “about” or “approximately” are taken tomean±10%, ±5%, ±2.5% or ±1% of a specified valued. As used herein, theterm “substantially” is taken to mean “to a large degree” or “at least amajority of” or “more than 50% of”

The above is a detailed description of particular embodiments of theinvention. It will be appreciated that, although specific embodiments ofthe invention have been described herein for purposes of illustration,various modifications may be made without departing from the spirit andscope of the invention. Accordingly, the invention is not limited exceptas by the appended claims. All of the embodiments disclosed and claimedherein can be made and executed without undue experimentation in lightof the present disclosure.

1) A method of treating viral infection in a subject in need thereof,the method comprising administering to the subject one or more doses ofan antiviral composition comprising digoxin, wherein said viralinfection is selected from the group consisting of flavivirus infection,Yellow Fever, Dengue Fever, Japanese Enchephalitis, West Nile virusinfection, Zikavirus infection, Tick-borne Encephalitis, Kyasanur ForestDisease, Alkhurma Disease, Omsk Hemorrhagic Fever, and Powassan virusinfection. 2) A prophylactic method of treating a subject at risk ofcontracting a viral infection, the method comprising chronicallyadministering to the subject one or more doses of an antiviralcomposition on a recurring basis over an extended treatment period priorto the subject contracting the viral infection, thereby preventing thesubject from contracting the viral infection; wherein the antiviralcomposition comprises digoxin, and wherein said viral infection isselected from the group consisting of flavivirus infection, YellowFever, Dengue Fever, Japanese Enchephalitis, West Nile virus infection,Zikavirus infection, Tick-borne Encephalitis, Kyasanur Forest Disease,Alkhurma Disease, Omsk Hemorrhagic Fever, and Powassan virus infection.3) The method of claim 1 comprising: determining whether or not thesubject has said viral infection; indicating administration of saidantiviral composition; administering an initial dose of said antiviralcomposition to the subject according to a prescribed initial dosingregimen for a period of time; periodically determining the adequacy ofsubject's clinical response and/or therapeutic response to treatmentwith said antiviral composition; and if the subject's clinical responseand/or therapeutic response is adequate, then continuing treatment withsaid antiviral composition as needed until the desired clinical endpointis achieved; or if the subject's clinical response and/or therapeuticresponse are inadequate at the initial dose and initial dosing regimen,then escalating or deescalating the dose until the desired clinicalresponse and/or therapeutic response in the subject is achieved. 4) Themethod according to any one of the above claims, wherein the viral titrein the subject's blood or plasma is reduced or does not increase as aresult of the treatment. 5) The method according to any one of the aboveclaims, wherein one or more doses are administered on a daily, weekly ormonthly basis. 6) The method according to any one of the above claims,wherein the administration is systemic, parenteral, buccal, enteral,intramuscular, subdermal, sublingual, peroral, oral, or a combinationthereof. 7) The method according to any one of the above claims, whereinsaid antiviral composition is administered immediately after infectionor any time within one day to 5 days after infection or at the earliesttime after definite diagnosis of infection with virus. 8) The methodaccording to any one of the above claims, wherein a dose comprises about100-1000 microg of antiviral composition per Kg of body weight of saidsubject. 9) The method according to any one of the above claims, whereinthe amount of digoxin administered per day is selected from the groupconsisting of 140 microg to 315 microg, 20 microg to 750 microg, 12microg to 300 microg, 12 microg to 120 microg, 0.01 microg to 100 mg,0.01 microg to 100 microg, about 0.5 to about 100 microg, about 1 toabout 80 microg, about 1.5 to about 60 microg, about 1.8 to about 60microg, or about 1.8 to about 40 microg. 10) The method according to anyone of the above claims, wherein a dose of said antiviral composition isadministered twice daily or about every 12 hours, and the amount ofdigoxin in said dose is about 0.25 to about 50 microg or about 0.9 to 5microg. 11) The method according to any one of the above claims, whereinthe daily dose of digoxin in said antiviral composition is a maximum ofabout 100 microg/day, about 80 microg/day, about 60 microg/day, about 40microg/day, about 38.4 microg/day or about 30 microg/day. 12) The methodaccording to any one of the above claims, wherein the daily dose ofdigoxin in said antiviral composition is a minimum of about 0.5microg/day, about 1 microg/day, about 1.5 microg/day, about 1.8microg/day, about 2 microg/day, or about 5 microg/day. 13) The methodaccording to any one of the above claims, wherein followingadministration of said one or more doses, the plasma concentration ofdigoxin in said subject is in the range of about 0.05 to about 2 ng/ml,about 0.005 to about 10 ng/mL, about 0.005 to about 8 ng/mL, about 0.01to about 7 ng/mL, about 0.02 to about 7 ng/mL, about 0.03 to about 6ng/mL, about 0.04 to about 5 ng/mL, or about 0.05 to about 2.5 ng/mL, interms of the amount of digoxin per mL of plasma. 14) The methodaccording to any one of the above claims, wherein said antiviralcomposition is administered as primary antiviral therapy, adjunctantiviral therapy, or co-antiviral therapy. 15) The method according toany one of the above claims, wherein said administration comprisesseparate administration or coadministration of said antiviralcomposition with at least one other antiviral composition or with atleast one other composition for treating symptoms associated with saidviral infection. 16) The method according to claim 15, wherein saidsymptoms are selected from the group consisting of inflammation,vomiting, nausea, headache, fever, diarrhea, nausea, hives,conjunctivitis, malaise, muscle pain, joint pain, seizure, andparalysis. 17) A method of treating viral infection in a subject in needthereof, the method comprising administering to the subject one or moredoses of an antiviral composition comprising digoxin, wherein said viralinfection is selected from the group consisting of flavivirus infection,Yellow Fever, Dengue Fever, Japanese Enchephalitis, West Nile virusinfection, Zikavirus infection, Tick-borne Encephalitis, Kyasanur ForestDisease, Alkhurma Disease, Omsk Hemorrhagic Fever, and Powassan virusinfection, wherein a dose a dose comprises about 100-1000 microg ofantiviral composition per Kg of body weight of said subject, or theamount of digoxin administered per day is selected from the groupconsisting of 140 microg to 315 microg, 20 microg to 750 microg, 12microg to 300 microg, 12 microg to 120 microg, 0.01 microg to 100 mg,0.01 microg to 100 microg, about 0.5 to about 100 microg, about 1 toabout 80 microg, about 1.5 to about 60 microg, about 1.8 to about 60microg, or about 1.8 to about 40 microg; and following administration ofsaid one or more doses, the plasma concentration of digoxin in saidsubject is in the range of about 0.05 to about 2 ng/ml, about 0.005 toabout 10 ng/mL, about 0.005 to about 8 ng/mL, about 0.01 to about 7ng/mL, about 0.02 to about 7 ng/mL, about 0.03 to about 6 ng/mL, about0.04 to about 5 ng/mL, or about 0.05 to about 2.5 ng/mL, in terms of theamount of digoxin per mL of plasma. 18) The method of claim 17, whereina) the daily dose of digoxin in said antiviral composition is a maximumof about 100 microg/day, about 80 microg/day, about 60 microg/day, about40 microg/day, about 38.4 microg/day or about 30 microg/day; and/or b)the daily dose of digoxin in said antiviral composition is a minimum ofabout 0.5 microg/day, about 1 microg/day, about 1.5 microg/day, about1.8 microg/day, about 2 microg/day, or about 5 microg/day. 19) Themethod of any one of claims 17-18, wherein the administration issystemic, parenteral, buccal, enteral, intramuscular, subdermal,sublingual, peroral, oral, or a combination thereof. 20) The methodaccording to any one of claims 17-19, wherein said antiviral compositionis administered as primary antiviral therapy, adjunct antiviral therapy,or co-antiviral therapy.